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15 November 2025

Impact of COVID-19 on Social, Economic, and Health Interventions for Tuberculosis and Leprosy

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1
Department of Pharmaceutical Sciences, Federal University of São Paulo, Prof. Artur Riedel Street, 275-Jardim Eldorado, Diadema 09972-270, SP, Brazil
2
Department of Public Health, FMABC University Center, Santo André 09060-870, SP, Brazil
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Department of Pathology, FMABC University Center, Santo André 09060-870, SP, Brazil
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Author to whom correspondence should be addressed.
Hygiene2025, 5(4), 53;https://doi.org/10.3390/hygiene5040053 
(registering DOI)
This article belongs to the Section Health Promotion, Social and Behavioral Determinants
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Abstract

Introduction: The COVID-19 pandemic disrupted social interactions, family dynamics, and economic stability, disproportionately affecting vulnerable populations. Tuberculosis and leprosy perpetuate poverty and, once manifested, hinder socioeconomic development due to their high potential for disability. Methodology: This study analyzed the impact of the COVID-19 pandemic using DATASUS health data and assessed the influence of socioeconomic interventions (SAGICAD data) on tuberculosis and leprosy case notifications in Brazil. A correlation analysis was performed between regional diagnoses and variables such as Bolsa Família (a national social welfare program), BCG vaccination coverage, and COVID-19 immunization rates, applying Pearson’s correlation test. Results: No significant correlations were found between COVID-19 vaccination rates and tuberculosis/leprosy diagnoses. However, a strong negative correlation (p < 0.05) was observed between BCG (Bacillus Calmette–Guérin) vaccination coverage and leprosy incidence in the Northern region. The findings also suggest that social assistance programs such as Bolsa Família play a pivotal role in preventing infectious diseases in vulnerable areas. Conclusions: Understanding the complex interplay between socioeconomic determinants and public health outcomes is essential for guiding future research and informing health policies, including potential revisions to social programs and vaccination protocols.

1. Introduction

The World Health Organization (WHO) officially declared COVID-19 a pandemic on 11 March 2020 []. According to data from Brazil’s State Health Departments, between 2020 and 2023 approximately 38,210,864 cases of COVID-19 were confirmed, with 708,638 deaths, yielding a mortality rate of 337.21 per 100,000 inhabitants []. Beyond disrupting social interactions and family dynamics, the pandemic exerted a profound impact on the national economy, disproportionately burdening vulnerable populations. Data from the Brazilian Institute of Geography and Statistics (IBGE) indicate that the unemployment rate increased from 11.5% in 2019 to 14.0% in 2021 [].
The Oswaldo Cruz Foundation (FIOCRUZ) [] reported a 38% increase in the homeless population between 2019 and 2022, reaching 281,572 individuals, many of whom lost both employment and housing during the crisis. Reduced access to essential services, including healthcare, further exacerbated health disparities and hindered timely disease diagnosis and treatment [].
COVID-19, caused by SARS-CoV-2, spreads primarily through respiratory droplets expelled by infected individuals—whether symptomatic, presymptomatic, or asymptomatic—during coughing, sneezing, or speaking []. Van Doremalen et al. (2020) demonstrated that SARS-CoV-2 remains viable in aerosols for several hours and on surfaces for multiple days, depending on the viral load, thereby enabling indirect transmission [].
Globally, approximately 10 million people develop tuberculosis (TB) each year, with the disease responsible for more than one million deaths annually []. In Brazil, about 70,000 new TB cases are reported every year []. The BRICS nations (Brazil, Russia, India, China, and South Africa) together account for 49% of global TB cases [], underscoring their central role in disease elimination strategies. As a major public health concern, TB can be caused by any of the seven species within the Mycobacterium tuberculosis complex, although M. tuberculosis (Koch’s bacillus) remains the most clinically significant []. Transmission occurs via the respiratory route when uninfected individuals inhale aerosols released by patients with active TB [].
The Brazilian Tuberculosis Control Guidelines [] indicate that mycobacteria may remain suspended in dark, poorly ventilated environments. Standard treatment consists of a six-month antibiotic regimen, with strict adherence being essential both for achieving cure and for interrupting transmission chains []. As demonstrated by Hargreaves et al. (2011), poverty, malnutrition, and food insecurity significantly increase susceptibility to infection [].
The World Health Organization (WHO) reports approximately 210,000 new leprosy cases worldwide each year, with Brazil ranking second only to India in case notifications for 2019. Leprosy is included in the United Nations’ 3rd Sustainable Development Goal (SDG 3), which aims to eliminate neglected tropical diseases by 2030 []. This chronic infectious disease, caused by Mycobacterium leprae [], primarily affects the peripheral nerves, eyes, and skin. Similarly to TB, transmission occurs through respiratory droplets from untreated infectious individuals. The disabling potential of the disease arises from the neurotropism and immunogenic properties of M. leprae [].
Multidrug therapy (MDT), consisting of a combination of antibiotics administered over 6–12 months depending on clinical response, represents the cornerstone of treatment. Strict therapeutic adherence is essential for achieving cure, preventing physical disabilities, and interrupting transmission [].
The convergence of COVID-19, tuberculosis (TB), and leprosy constitutes a syndemic—defined as the synergistic interaction of multiple epidemics, amplified by socioeconomic disparities, environmental factors, and health system vulnerabilities—resulting in compounded impacts on population health [,].
In response to the urgent need to address overlapping health burdens, the Brazilian Federal Government implemented targeted social assistance programs to mitigate the pandemic’s disproportionate impact on vulnerable populations. The most significant of these interventions was the Auxílio Emergencial (Emergency Aid Program), which provided financial support to 67.9 million socioeconomically vulnerable Brazilians during the crisis []. Established under Law No. 13.982/2020, this means-tested cash transfer program was specifically designed to provide immediate relief. According to Brazil’s Social Security Commission, social programs such as Bolsa Família (PBF) are structured around three core pillars: cash transfers to alleviate poverty in the short term; conditionalities to promote access to education and healthcare; and complementary initiatives aimed at family development, as a result of this structure, by June 2023, Bolsa Família and related social protection programs had lifted approximately 18.52 million households out of poverty, raising the average per capita monthly income to US$40 (around R$218), a figure above Brazil’s official poverty line [,]. In 2023, the program represented an average monthly expenditure of R$14.1 billion, reaching about 21.3 million families and amounting to an annual cost of nearly R$169 billion (Secom/Government of Brazil). This investment corresponded to approximately 1.5% of the national GDP, underscoring Bolsa Família as one of the most significant social protection policies in the country [].
The pandemic exposed significant vulnerabilities in health systems and social assistance programs across multiple regions. Examining the effects of these policies on notifiable diseases is essential for identifying effective strategies and areas requiring improvement. This study advances the field by analyzing the impacts of COVID-19 using data from DATASUS/TABNET, the Vacinômetro (Immunization Monitor), and SAGICAD, with a particular focus on tuberculosis and leprosy—diseases that disproportionately affect vulnerable populations. Given their strong association with poverty, evaluating the effectiveness of social and public health programs is especially critical during health emergencies. The findings may help inform future interventions and strengthen public policies, ultimately contributing to improved population health outcomes.

2. Materials and Methods

The first stage of the research involved defining the study theme and mapping notifiable diseases eligible for inclusion in the analysis, with tuberculosis and leprosy ultimately selected due to their similar immunological infection profiles and their strong association with socioeconomic development indicators.
Data were collected by region of Brazil (Midwest, Northeast, North, Southeast, and South), along with annual population estimates for each region between 2019 and 2023. The information was extracted from the reports Estimates of the Resident Population in Brazil and Federation Units with the following reference dates: 1 July 2019; 1 July 2020; and 1 July 2021. Three tables were generated, one for each year (2019, 2020, and 2021). No updated estimates were available for the years 2022 and 2023 [].
Subsequently, data were extracted from the official DATASUS/TabNet website []. The number of tuberculosis diagnoses by region of Brazil for each year between 2019 and 2023 was obtained from the Epidemiological and Morbidity dataset, specifically from Tuberculosis Cases—Since 2001 (SINAN) and Brazil by region, state, and municipality. On September 20, 2023, the TUBERCULOSIS table was generated with the following specifications: rows (Year of Diagnosis), columns (Region of Notification), content (Confirmed Cases), and period (2019–2023). Subsequently, an additional table, TUBERCULOSIS 2, was generated with the same specifications: rows (Year of Diagnosis), columns (Region of Notification), content (Confirmed Cases), and period (2019–2023) [].
For leprosy, data were also extracted from DATASUS [], specifically from the dataset Monitoring of Leprosy Data—Brazil. Four tables were generated with the same structure—rows (Year of Diagnosis) and columns (Region of Notification)—one for each year of the study period (2019–2023), but with different contents: Frequency, Skin Lesions, Registered Contacts, and Examined Contacts []. In addition to these datasets, information on BCG and BCG Leprosy doses was obtained from the Immunization—Since 1994 dataset, which belongs to the Health Care database. Five tables were generated, one for each year of interest (2019–2023), with the following structure: rows (Region), columns (Non-active), and measures (Doses Applied). COVID-19 vaccination data were retrieved from the COVID-19 Vacinômetro [], provided by the Ministry of Health. An Excel table was created with data on the total number of COVID-19 vaccine doses administered by each Brazilian state. Subsequently, the states were grouped by region, and the sum formula was applied to calculate the total number of doses administered per region.
The vaccination data were further filtered by type of dose administered in order to generate more detailed information. For this purpose, all regions of Brazil were selected, and the following fields were defined: State (UF), Health Micro-Region, Health Region, Municipality, Vaccine Month, Vaccine Date, and Vaccine. Separate tables were generated for each year (2021, 2022, and 2023), categorized by dose type: First Dose, Second Dose, Third Dose, Single Dose, Booster Dose, Additional Dose, First Booster Dose, Second Booster Dose, and Third Booster Dose, totaling 27 tables. For each table, the data were processed in the same manner as the total number of doses applied per region described above. Specifically, the data were transferred to an Excel spreadsheet, where the states were grouped by region, and the sum function was applied to calculate the total number of doses administered by region for each dose type [].
Finally, data on the distribution of income transfer programs were extracted in October 2023 using the Data Explorer tool on the website of the Secretariat for Evaluation, Information Management, and Unified Registry (SAGICAD) []. Information on the Bolsa Família Program was obtained with the following filters applied: Region (All Regions) and Period (2019 and 2023). It is important to note that no data were generated for 2022, as the benefit was temporarily replaced that year by Auxílio Brasil [,,,].
Emergency Aid data were obtained from the same SAGICAD source, using the keyword “Emergency Aid” and the record “Total People Assisted by Emergency Aid.” The dataset was then filtered by Region (All Regions) and Period (April 2020 to October 2021) [,].
Data on Auxílio Brasil were also retrieved from SAGICAD, using the keyword “Auxílio Brasil” and the record “Amount Transferred of Benefits by Type.” The dataset was then filtered by Region (All Regions) and Period (November 2021 to December 2022) [,].
After data extraction, line graphs were constructed to illustrate the temporal trends in the number of tuberculosis and leprosy diagnoses over the study period. Subsequently, correlations between regional diagnoses in Brazil and the variables Bolsa Família, BCG doses, and COVID-19 vaccine doses were assessed using Pearson’s correlation test. All analyses were performed with a 95% confidence level. Statistical procedures were conducted using Stata, version 16.0.

3. Results

The results demonstrate a progressive increase in tuberculosis diagnoses in the North and Northeast regions between 2019 and 2021, with annual growth rates ranging from 12 to 15%, followed by stabilization in 2022–2023. In contrast, the Southeast region exhibited a continuous decline of approximately 10% per year beginning in 2020, amounting to an overall reduction of 30% during the study period. The South and Central-West regions presented more stable patterns, with annual variations around 5%, and remained substantially below the national average—showing 40% and 25% fewer cases, respectively, in 2023. An alarming finding revealed that, in 2023, the North and Northeast regions together accounted for 60% of all national cases, underscoring persistent regional disparities in disease control. The pandemic period (2020–2021) further exacerbated these disparities: while the Southeast recorded an average decline of 12% in diagnoses, the North experienced a 7% increase, likely reflecting differences in the capacity to sustain health surveillance services during the health crisis. These regional trajectories are demonstrated in Figure 1, which illustrates the temporal distribution of tuberculosis cases by region of Brazil from 2019 to 2023, highlighting the pandemic’s peak impact.
Figure 1. Temporal distribution of tuberculosis cases by region of Brazil (2019–2023), highlighting the period of greatest impact of the COVID-19 pandemic. (Source: Prepared by the authors).
The trend in leprosy diagnoses from 2019 to 2023 revealed a slight overall decline, differing from the pattern observed for tuberculosis. Between 2020 and 2021, leprosy diagnoses decreased by 15%—likely reflecting the impact of COVID-19—followed by a recovery in most regions, except in the Southeast. Across the study period, leprosy cases were unevenly distributed throughout Brazil, with the Northeast (12,000–14,000 cases/year) and North (8000–10,000 cases/year) together accounting for 70–80% of national diagnoses. The Southeast experienced a 33% reduction, while the South and Central-West consistently presented the lowest case volumes (2000–4000 annually). In 2023, the Northeast and North reported further reductions of 5% and 8%, respectively. These findings are depicted in Figure 2, which demonstrates the temporal distribution of leprosy cases across Brazilian regions between 2019 and 2023.
Figure 2. Temporal distribution of leprosy cases by region of Brazil (2019–2023). (Source: Prepared by the authors).
BCG vaccination against tuberculosis accounted for 3,774,135 doses in the Southeast, 2,911,030 in the Northeast, 1,436,599 in the South, 1,203,766 in the North, and 896,741 in the Central-West. For BCG vaccination against leprosy, the Northeast reported 59,419 doses (83% of the national total), followed by the Southeast (33,726), South (14,086), Central-West (10,922), and North (5942). These data are detailed in Table 1A,B, which demonstrate the regional distribution of BCG and COVID-19 vaccination and leprosy prevalence rates from 2019 to 2023.
Table 1. BCG, BCG-Leprosy, and COVID-19 vaccination by region of Brazil (2019–2023), combined with the total number of doses administered per region and leprosy prevalence rates during the period. (A) BCG vaccination (2019–2023) and COVID-19 vaccination (total doses administered by region, 2021–2023). (B) Leprosy prevalence rates by region of Brazil (2019–2023).
Regarding COVID-19 vaccination, the Southeast registered 180,458,992 doses (48% of the national total), followed by the Northeast (98,088,012), South (42,790,374), Central-West (23,524,999), and North (20,632,887). The disparity between the Southeast and North was particularly striking, with the former administering 8.7 times more doses than the latter.
The analysis of leprosy cases presenting with skin lesions in Brazil (2019–2023) included the percentage of cases, p-values from the Chi-square test, and Prevalence Ratios (PR). In the Northeast, the proportions were 40.81% (2019), 40.92% (2020), 41.12% (2021), 41.76% (2022), and 39.41% (2023), with p-values below 0.05, indicating statistical significance. PR values were not provided for this region, as the Northeast served as the reference group. In the North, the proportions were 19.44%, 17.17%, 16.99%, 17.06%, and 18.11%, with PR ranging from 2.10 to 2.45. In the Southeast, the proportions were 14.61%, 15.47%, 17.04%, 16.96%, and 15.31%, with PR values ranging from 2.41 to 2.79. In the South, proportions ranged from 4.60% to 5.84%, with PR between 6.75 and 8.90. In the Central-West, proportions ranged from 17.46% to 20.64%, with PR between 1.98 and 2.34. Overall, the Northeast showed an average PR of 2.30, higher than all other regions.
The correlation between leprosy and receipt of the Bolsa Família benefit, measured by Spearman’s rho, was negative across all regions. In the North (ρ = −0.58), Northeast (ρ = −0.54), Southeast (ρ = −0.49), South (ρ = −0.45), and Central-West (ρ = −0.50), these correlations were not statistically significant. For tuberculosis, the correlation with Bolsa Família was also negative but stronger, particularly in the Southeast (ρ = −0.96, p = 0.030) and South (ρ = −0.97, p = 0.032), where it reached statistical significance.
The analysis of the correlation between diagnoses and BCG doses revealed a weak correlation between tuberculosis and BCG in the North (ρ = 0.44, p = 0.710), but a strong and statistically significant negative correlation with leprosy (ρ = −0.99, p = 0.031). In the Northeast, Southeast, South, and Central-West, no statistically significant correlations were found between BCG and either tuberculosis or leprosy, although some moderate associations were observed.
Regarding the correlation between COVID-19 vaccination and diagnoses, in the North a strong positive correlation was observed with tuberculosis (ρ = 0.98), although it did not reach statistical significance (p = 0.121). In the Northeast, Southeast, South, and Central-West, positive correlations were also observed, but none were statistically significant.
Finally, the correlation between tuberculosis and leprosy diagnoses and the number of COVID-19 vaccine doses administered was assessed in each region of Brazil. Throughout the period from 2018 to 2023, no statistically significant associations were identified between the number of COVID-19 vaccine doses and the number of tuberculosis or leprosy diagnoses.

4. Discussion

During the COVID-19 pandemic years, an increase in tuberculosis diagnoses was observed, which may suggest a negative impact on the detection and treatment of the disease. These findings contrast with reports in the literature, as the Pan American Health Organization indicated that, in 2020, the Americas experienced an increase in tuberculosis-related deaths alongside a reduction in confirmed diagnoses compared with previous years []. The rise in mortality has been attributed to the ease of transmission in overcrowded environments and poor hygiene conditions—factors that became more critical during the pandemic, particularly among the most vulnerable populations. The increase in tuberculosis diagnoses shown in Figure 1 may also reflect underreporting of cases in the years preceding the pandemic or reduced health-seeking behavior among affected individuals. A deeper analysis is warranted to assess the accuracy of the information provided to DATASUS.
Despite the gradual reduction in tuberculosis incidence and mortality over the past decade, the global burden of the disease remains high, with more than 10 million cases reported annually. Although this downward trend represents progress toward the goals of the WHO’s End TB Strategy and the United Nations’ Sustainable Development Goals (SDGs), these advances were severely compromised by the COVID-19 pandemic. The global health crisis led to a sharp decline in diagnosis and access to tuberculosis-related services, particularly in low- and middle-income countries (LMICs). According to WHO data, the number of reported cases fell by 18% in 2020 compared with 2019, reversing nearly a decade of progress. This setback outweighed any potential indirect benefits, such as reduced Mycobacterium tuberculosis transmission resulting from mask use and social distancing. Moreover, the impacts persist in light of the unequal distribution of SARS-CoV-2 vaccines, which has further undermined tuberculosis control, as well as efforts to address other priority infectious diseases such as HIV and malaria [].
During the COVID-19 pandemic, a decrease in leprosy cases was observed in Brazil, consistent with the expected trend. Previous studies [] reported a significant reduction in the number of leprosy diagnoses across all regions of the country. The Southeast recorded the largest decline, with a reduction of 45.8%, followed by the Northeast with a 40.5% decrease. The South, North, and Central-West also showed substantial declines, of 39.5%, 39.2%, and 36.8%, respectively. Overall, the analysis revealed a nationwide reduction in leprosy incidence, with the Southeast and Northeast exceeding the national average decline. This decrease in diagnoses may be associated with the COVID-19 pandemic, compounded by the overload of the health system and the population’s fear of seeking medical care. It is also important to emphasize that leprosy is transmitted via aerosols, which suggests that the social isolation imposed during the pandemic may have contributed to the lower number of reported cases []. These regional patterns are consistent with the trends demonstrated in Figure 2, where a marked decline during 2020–2021 is followed by a gradual recovery in most regions.
These findings underscore the need for measures that guarantee continuous access to health services and raise awareness of the importance of early diagnosis and appropriate treatment of leprosy, even during public health crises such as the COVID-19 pandemic.
A study based on spatial analysis demonstrated that although COVID-19, tuberculosis, and leprosy share the same mode of transmission, their incidence patterns in Fortaleza are distinct. While COVID-19 and tuberculosis showed a more homogeneous distribution, leprosy was concentrated in specific areas of the southern and western regions, with the Pedras neighborhood identified as a critical hotspot of overlap for the three diseases. These findings underscore the importance of understanding territorial heterogeneity to guide surveillance and intervention strategies. From a socioeconomic perspective, higher levels of literacy and income were associated with increased incidence of COVID-19, suggesting the influence of mobility and exposure factors. In contrast, low levels of education and income remained strongly associated with tuberculosis and leprosy, confirming the persistence of social vulnerability as a key determinant. These results highlight the need for prevention strategies that combine integrated approaches in areas of overlap with targeted actions addressing the socioeconomic inequalities that shape the dynamics of each condition [].
The data presented indicate that leprosy does not affect the population uniformly. The Northeast of Brazil shows substantially higher prevalence rates compared with other regions. In 2023, an individual in the Northeast had approximately a 40% likelihood of developing leprosy, whereas in the North this likelihood was 19%, and in the South it dropped to nearly 6%. Not coincidentally, the North and Northeast regions also exhibit the most unfavorable social and economic indicators, including high unemployment rates, and account for the largest share of Bolsa Família program beneficiaries [].
According to IBGE data, in December 2023 approximately 21,064,289 families received benefits from the Bolsa Família program, representing nearly 28% of all Brazilian households. The regional distribution was as follows: the Northeast, with 9.48 million beneficiary families; the Southeast, with 6.28 million; the North, with 2.6 million; the South, with 1.48 million; and the Midwest, with 1.18 million [].
Although there is a correlation between unfavorable socioeconomic conditions and the increased incidence of leprosy, it cannot be stated that families receiving benefits from the Bolsa Família program are directly associated with higher prevalence rates of the disease, since the correlation between leprosy diagnoses and receipt of the benefit was not statistically significant. On the other hand, factors such as income, housing quality, and educational level play a critical role in determining the risk of leprosy, as they are strongly shaped by structural determinants including poverty, low income, and broader socioeconomic inequalities.
When examining the correlation between tuberculosis diagnoses and receipt of Bolsa Família benefits, a strong and statistically significant negative correlation was observed in the South and Southeast regions. This indicates that as the number of families benefiting from the program increases, the number of tuberculosis diagnoses tends to decrease, and vice versa. Among the ten cities with the highest cost of living in Brazil, six are located in the Southeast, two in the South, one in the Midwest, and one in the Northeast. This suggests that in the South and Southeast, financial support from income distribution programs has a substantial impact on beneficiaries’ lives by ensuring access to minimum subsistence conditions []. These relationships are consistent with the correlation patterns reported in Table 2, which illustrate the inverse association between tuberculosis diagnoses and social protection coverage in these regions.
Table 2. Spearman correlation coefficients between tuberculosis and leprosy diagnoses, vaccination coverage (COVID-19 and BCG), and social programs (Bolsa Família), stratified by region of Brazil (2019–2023).
According to the World Bank, the negative economic impacts of the pandemic have been more severe for the poor and vulnerable populations in Brazil. The deterioration of the labor market has led to a reduction in income, particularly affecting the most vulnerable 40% of the population. Moreover, lack of access to technology and educational opportunities remains a common challenge among individuals living in poverty, limiting their ability to adapt to changes in the labor market brought about by COVID-19. These findings underscore the importance of the Bolsa Família program as an effective measure to improve living conditions and potentially contribute to reducing tuberculosis cases in these regions [].
The data presented on the correlation between tuberculosis and leprosy diagnoses and the number of BCG doses administered were collected to assess the efficacy of vaccination, the most relevant form of prevention against both diseases. The statistical analysis focused on the relationship between the number of BCG doses administered and the number of reported diagnoses, providing important insights into the association between vaccination coverage and the incidence of leprosy and tuberculosis. As demonstrated in Table 1A,B, regional differences in vaccination coverage and leprosy prevalence highlight the heterogeneity of disease distribution and immunization performance across Brazil.
Currently, the vaccination protocol adopted in Brazil recommends the administration of a single dose of the BCG vaccine to children shortly after birth. This is because BCG provides protection against the most severe forms of tuberculosis, particularly during the first years of life. At present, BCG is the only licensed vaccine for the prevention of TB, offering moderate protection against severe disease in infants and young children. It is widely available through national immunization programs, playing a vital role in preserving young lives and preventing severe outcomes []. However, it is important to emphasize that there is no effective vaccine capable of preventing tuberculosis in adults, either before or after exposure to infection. Although promising results have been reported from a Phase II clinical trial of the M72/AS01E vaccine candidate, among the 14 candidates currently under clinical investigation for adult immunization against TB, it is likely that these vaccines will only become available in the coming years []. It is well established that increasing the number of BCG doses administered does not lead to a reduction in tuberculosis or leprosy cases among adults. Only the North region showed a strong and statistically significant negative correlation between the number of BCG doses administered and the incidence of leprosy.
In light of these findings, it is important to consider revising the vaccination protocol and investing in research for the development of vaccines capable of providing protection against the disease in adulthood. Given the limited effectiveness of the current vaccination protocol, it is important to consider its revision and to promote the development of vaccines that provide protection against tuberculosis and leprosy in adults. Moreover, considering the relatively high fertility rates among low-income populations in Brazil, immunizing working-age adults may be more effective than vaccinating young children in promoting long-term economic growth []. These measures may be fundamental in addressing the challenges related to tuberculosis across all age groups. Such information is essential for monitoring vaccination coverage and assessing the impact of immunization campaigns in each region, thereby supporting the evaluation and planning of vaccination programs. The COVID-19 vaccine does not provide protection against tuberculosis or leprosy; however, its rollout enabled the relaxation of restrictions, the resumption of mass mobility, and the reintegration of individuals who had lost their jobs or were unable to work remotely.
Although the COVID-19 vaccine does not provide protection against tuberculosis or leprosy, this correlation remains important, as vaccination enabled the relaxation of restrictions, the resumption of mass mobility, and, most importantly, the reintegration of individuals who had lost their jobs or were unable to work remotely. At present, there is limited literature addressing tuberculosis or leprosy in the post-pandemic period. Future studies should assess the relationship between tuberculosis and leprosy diagnoses and factors such as unemployment rates, access to basic sanitation, and the average number of individuals per household. These analyses can provide valuable insights into the socioeconomic factors that affect the incidence of these diseases after the pandemic.
Evidence in the literature indicates that, in addition to its efficacy in the prophylaxis of tuberculosis, the BCG vaccine exerts immunomodulatory effects capable of providing cross-protection against various infectious agents, including respiratory viruses. This review analyzed different BCG strains used globally, as well as the immunological mechanisms they trigger. Of particular note is the induction of trained innate immune responses, mediated by epigenetic alterations in cells such as monocytes, macrophages, and natural killer cells, which play a central role in controlling viral infections. In this context, certain BCG strains demonstrate potential to act as adjuvants of baseline immunity and may represent a complementary strategy in addressing COVID-19 and future pandemics, even with the availability of specific vaccines [].
The relationship between COVID-19 and tuberculosis warrants further investigation, as both share the respiratory route as their primary mode of transmission and directly impact the immune response. Moreover, the potential effect of BCG vaccination on COVID-19 outcomes has been hypothesized by Brazilian researchers. This reinforces the need for additional studies on the interaction between vaccines, innate immunity, and outcomes in respiratory diseases. In addition, correlation coefficients involving COVID-19 vaccination should be interpreted with caution, since the available data cover only the period from 2021 to 2023, thereby limiting temporal variability and potentially generating artificially elevated values of association. This methodological limitation, already noted in Table 2, reinforces the need for cautious interpretation of high Spearman coefficients related to vaccination variables.
International literature emphasizes that the COVID-19 pandemic constituted a multidimensional event, with particularly severe health, social, and economic repercussions in low- and middle-income countries. This crisis exacerbated historical determinants of tuberculosis, such as poverty, food insecurity, malnutrition, and inadequate housing conditions, posing a threat by reversing progress achieved over the past decade. The reallocation of human and material resources to COVID-19 response efforts led to a substantial decline in tuberculosis diagnosis and treatment, increasing the number of unreported cases and elevating the risk of community transmission. In addition, interruptions in drug supply and nutritional support, as well as greater household exposure during lockdown periods, contributed to the progression of latent infections into active disease. In light of this scenario, it is imperative to adopt integrated strategies that combine social protection, strengthening of health services, diagnostic integration between COVID-19 and TB, as well as investments in research and community mobilization, in order to mitigate the synergistic effects of the pandemic and tuberculosis [].

5. Conclusions

In conclusion, this analysis revealed that the COVID-19 pandemic had distinct impacts on the notification rates of leprosy and tuberculosis in Brazil. The study found no statistically significant correlations between the number of COVID-19 vaccine doses administered and tuberculosis or leprosy diagnoses. It is well established that increasing the number of BCG doses does not reduce tuberculosis or leprosy cases among adults. An exception was observed in the Northern region, where a strong and statistically significant negative correlation was identified between BCG vaccination rates and leprosy diagnoses. Nevertheless, the findings suggest that social assistance programs such as Bolsa Família play a crucial role in infectious disease reporting, particularly in regions marked by greater socioeconomic vulnerability and inequality. Further in-depth evaluation is warranted to better elucidate the complex interactions between socioeconomic determinants and public health, especially during crises such as the COVID-19 pandemic. These insights are essential to inform future research and guide public policy revisions, including the evaluation of social program effectiveness and the reexamination of current vaccination protocols.

Author Contributions

L.A. actively participated in the conception and design of the study, contributed to the writing of the manuscript, focusing on the introduction and methodology, reviewed and approved the final version of the article, and assumes responsibility for the integrity and accuracy of the work. J.d.C.R. assisted in the development of the methodological design, critically reviewed the manuscript, especially in the data analysis, approved the final version and is committed to the integrity of the work. I.B.L. contributed to the conception of the research and definition of the objectives, participated in the writing of the discussion and conclusions, approved the final manuscript and assumes responsibility for the content of the work. G.L.d.V. assisted in the design of the methodology and data collection, critically reviewed the manuscript, with emphasis on the results, approved the final version and ensures the accuracy of the data presented. B.d.C.A.A. participated in the conception of the study and definition of the hypotheses, contributed to the writing of the literature review, approved the final manuscript and assumes responsibility for the integrity of the work. E.C.P. contributed to the definition of the objectives and hypotheses, participated in the writing of the discussion and revision of the manuscript, approved the final manuscript and assumes responsibility for the content of the work. L.V.d.A.S. assisted in the planning of the statistical analysis, critically reviewed the results and methods section, approved the final version and is committed to the accuracy of the data and analyses. F.L.A.F. assisted in the design of the research and in the definition of the methodology, critically reviewed the manuscript, focusing on clarity and coherence, approved the final version and ensures the integrity and accuracy of the work. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

Not applicable.

Data Availability Statement

The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.

Acknowledgments

The authors have reviewed and edited the output and take full responsibility for the content of this publication.

Conflicts of Interest

The authors declare no conflicts of interest.

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Medication Adherence in Kosovo—Healthcare Key Opinion Creators’ Perspective
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