Allergic Reactions to COVID-19 Vaccination in High-Risk Allergic Patients: The Experience of Trieste University Hospital (North-Eastern Italy)

Background. Allergic patients may develop reactions following COVID-19 vaccination more frequently than non-allergic individuals. The aim of our study was to assess the risk of reactions in high-risk allergic patients vaccinated for COVID-19 at the University Health Agency Giuliano-Isontina (ASUGI) of Trieste (northeastern Italy). Methods. Patients were considered at high risk for allergic reactions in case of: prior anaphylactic reaction to any drug/vaccine; multiple drug allergy; intolerance to polyethylene glycol (PEG) or polysorbate 80 (PS80) containing drugs; and mast cell disorders. High-risk allergic patients were immunized in hospital by a dedicated allergy team supported by resuscitation staff. Patients were interviewed over the phone one month after vaccination to complete a structured questionnaire investigating signs and symptoms developed after immunization. Results. From March 2021 to February 2022, 269 patients with a history of severe allergic reactions were assessed, of whom 208 (77.3%) eventually received COVID-19 vaccination, 50 (18.6%) refused to be immunized, 10 (3.7%) were deferred for medical reasons and one was declared exempted due to testing positive for PS80. Mild reactions (urticaria, angioedema, rhinitis, erythema) to COVID-19 vaccines were reported by 30.3% of patients, 8.7% within 4 h and 21.6% > 4 h after immunization. No anaphylactic events were observed. Although they were 80 times (3.8%) more prevalent than in COVID-19 vaccinees from the general population (0.047%), vaccine allergic reactions in high-risk patients were mainly mild and late, more likely affecting women (OR = 3.05; 95% CI 1.22–7.65). Conclusions. High-risk allergic patients with urticaria and angioedema may experience mild flare-ups of mast cell activation-like symptoms following COVID-19 vaccination, supporting antihistamine premedication before vaccination and to be continued for one week afterwards.


Introduction
In Italy, the vaccination campaign against COVID-19 started on 27 December 2020. COVID-19 vaccination was made mandatory for all health care workers (HCWs) from April 2021 and for individuals older than 50 from January 2022 onward. Unvaccinated HCWs were suspended from work or re-assigned to work tasks not entailing patient contact.
At the University Health Agency Giuliano-Isontina (ASUGI), the vaccination campaign against COVID-19 started with Comirnaty (Pfitzer-BioNTech, BNT162b2) and Vaxzevria (Astra Zeneca), and from May 2021 Spikevax (Moderna) was introduced. The risk of allergic reactions to COVID-19 vaccines was immediately a matter of concern due to the exclusion of allergic patients in phase-three clinical studies on Comirnaty [1] and patients with a history of allergic reaction to any component of COVID-19 vaccine or an allergy to other vaccines in Spikevax trials [2,3].
The risk of anaphylaxis after vaccination with Comirnaty was 11.1 per million injections in an initial report from the USA [4] and 4.7 cases per million doses in a greater population of vaccinees [5], an estimate 5-10 times higher than that reported for other non-COVID-19 vaccines [6].
Polyethylene glycol (PEG) and tromethamine for mRNA vaccines and polysorbate 80 (PS80) for Vaxzevria were immediately indicted as possible culprit allergens for allergic reactions [7] and specific recommendations were suggested to screen patients with a history of allergic reactions before immunizing them with COVID-19 vaccines [8][9][10].
In view of the above, the aim of this study was to assess allergic reactions following COVID-19 vaccination among high-risk allergic patients in ASUGI Trieste.

Materials and Methods
The present study was conducted according to the guidelines of the Declaration of Helsinki and approved by the ethical committee of the Friuli-Venezia Giulia region (CEUR-2020-Os-072) on 16 April 2020. Patient consent was waived since, according to Italian privacy law (Legislative Decree 101/2018, D.Lgs 101/2018), patients' data routinely collected by the Italian National Health Service (NHS) can be used for scientific purposes within the scope of approved studies/protocols, provided sensitive information is anonymized.
At the Unit of Occupational Medicine of Trieste Teaching Hospital, an allergy task force (ATF) was set up to assess the risk of allergic reactions to COVID-19 vaccines in high-risk allergic patients and their eligibility for vaccination within the catchment area of the health district of Trieste. General practitioners and health care staff at COVID-19 vaccination centers referred high-risk individuals with history of severe allergic reactions for immunization under special medical supervision.
In accordance with the open literature [7,9] and the guidelines of the Italian Association of Allergologists and Immunologists [11], patients with sensitivity to aeroallergens, latex, or contrast media, as well as patients with single-drug or venom allergy, were immunized under standard conditions and monitored for 60 min after vaccination. Patients meeting the following criteria underwent medical assessment by the ATF:

•
History of allergic or anaphylactic reaction to multiple oral or injectable drugs or vaccines; • History of idiopathic anaphylaxis; • History of mast cell disorders; • History of chronic urticaria; • History of uncontrolled asthma.
Multiple drug allergy was defined as a history of hypersensitivity to more than 1 drug group. An allergy workout was set up to evaluate drug intake in patients and their tolerance to excipients such as PEG and PS80.
Patients were considered at high risk of allergic reactions in case of: • Prior anaphylactic reaction to any drug or vaccine; • Multiple drug allergy without tolerance to PEG-or PS80-containing drugs; • Mast cell disorders; • Patients with uncontrolled asthma who had to be treated for their condition to achieve satisfactory control of their symptoms before being vaccinated for COVID-19.
Patients considered at high risk of allergic reaction were immunized in a hospital setting and monitored for 1-2 h following vaccination by a dedicated allergy team, including resuscitation medical staff. Although patients had to continue their usual anti-allergic therapy post immunization, including antihistamines [7], premedication was not recommended before any COVID-19 vaccine dose [11]. Upon administration of the second and third dose of the COVID-19 vaccine, health care staff asked vaccinees to report any reactions to previous doses. One month after immunization, patients were contacted by the ATF over the phone to complete a structured survey questionnaire investigating the signs and symptoms developed after any COVID-19 vaccine dose. Early adverse reactions were defined as those occurring within minutes to 4 h after vaccine administration; late reactions were defined as those developing >4 h after immunization [7,12]. Local reactions at the site of the injections were not considered in the analysis. Definitions of some immunological conditions and technical terms used across this manuscript can be viewed in Supplementary Table S1 [13][14][15][16][17].

Statistical Analysis
The data of patients developing reactions were compared with those not developing reactions.
Continuous data were reported as median (interquartile range, IQR) and mean ± standard deviation and compared using the Mann-Whitney test. Categorical data were compared by chi-square statistics.
Prevalence of allergic reactions in the study population was compared to that in the general population of the same area (Provinces of Trieste and Gorizia) obtained from regional surveillance system for reactions to COVID-19 vaccines.
A multivariable logistic regression was used to investigate risk factors for allergic reactions post COVID-19 vaccination, selecting terms significant at univariable analysis.
No variable had missing values. A p-value < 0.05 was set as a threshold for statistical significance.
Statistical analysis was performed using STATA 17 (STATA Corp, University City, TX, USA).

Results
Two hundred and sixty-nine patients with history of allergic reactions were assessed by the ATF of Trieste from March 2021 to February 2022. As can be seen from Figure 1, among the latter high-risk allergic group: • 208 (77.3%) patients received COVID-19 vaccination; • 50 (18.6%) patients refused to be immunized; • 10 (3.7%) patients were deferred for medical reasons (uncontrolled asthma, ongoing urticarial reactions, other acute allergic diseases); • 1 patient tested positive for PEG and PS80 and was declared exempt from mandatory vaccination against COVID-19.
As can be seen from Table 1, high-risk allergic patients of ASUGI Trieste were predominantly females (79.6%) and had a median age of 55 years (IQR: 45-64 years). Moreover, 53.5% (=144/269) of patients had a history of drug allergy and 18.2% (=49/269) reported drug anaphylaxis. Food allergy was reported by 69 (25.6%) patients and 2.6% (=7/269) with food anaphylaxis. Eighteen patients underwent skin tests for PEG, none of whom were positive, whereas three were tested for PS80 with only one turning up positive.
One hundred and twenty patients were vaccinated under special medical supervision. Mild allergic reactions (urticaria, angioedema, rhinitis and erythema) post COVID-19 vaccinations occurred in 30.3% patients, 8.7% early (within 4 h) and 21.6% late (>4 h) after immunization.  As can be seen from Table 1, high-risk allergic patients of ASUGI Trieste were predominantly females (79.6%) and had a median age of 55 years (IQR: 45-64 years). Moreover, 53.5% of patients had a history of drug allergy and 49 (18.2%) reported drug anaphylaxis. Food allergy was reported by 69 (25.6%) patients and 7 more developed food anaphylaxis. Eighteen patients underwent skin tests for PEG, of which none were positive, whereas three were tested for PS80 with only one turning up positive.
One hundred and twenty patients were vaccinated under special medical supervision. Mild allergic reactions (urticaria, angioedema, rhinitis and erythema) post COVID-19 vaccinations occurred in 30.3% patients, 8.7% early (within 4 h) and 21.6% late (> 4 h) after immunization.     Table 2 displays the results of univariable as well as multivariable logistic regression analysis investigating risk factors for allergic reactions to COVID-19 vaccinations. As can be seen, females were more likely to develop an allergic reaction (OR = 3.05; 95% CI: 1.22; 7.65), whereas patients withhistory of allergic reactions to drugs had a significantly lower risk of reaction (OR = 0.30; 95% CI: 0.15; 0.58).   The details of the adverse reactions in each patient by COVID-19 vaccine dose in each patient can be viewed in Table 3. As can be seen, no allergic reaction within or after 4 h since COVID-19 vaccination involved two districts simultaneously (skin as well as respiratory system). Among the study group: • 29 patients developed an allergic reaction only to the first vaccine dose (orange coloured), of whom 8 were referred to ATF medical examination before dose 1 and 21 between dose 1 and dose 2. • 11 patients developed an allergic reaction only after the second vaccine dose (green coloured), of whom 3 were referred to ATF medical examination before dose 1 and 8 between dose 1 and dose 2. • 3 patients developed an allergic reaction only to the third dose (yellow coloured), all referred to ATF medical examination before dose 1. • 17 patients reacting to the first vaccine dose reacted also to the second (grey colored), of whom 5 were referred to ATF medical examination before the first dose and 12 between dose 1 and dose 2; • 2 patients referring to AFT medical examination before the first dose did not develop any allergic reaction to the first dose, but reacted after both dose 2 as well as dose 3 (pink colored); • 1 patient referring to ATF between first and second dose reacted against both dose 1 as well as dose 2; • No patient was referred to ATF medical examination after the second dose of COVID-9 vaccine.    Table 4 reports the aggregated adverse and allergic reactions to d vaccines in the general population of the Trieste-Gorizia catchment ar dose administered. The overall prevalence of allergic reactions was 0. doses administered in 2021) and only eight vaccinees were recorded in surveillance system for adverse vaccine events. No cases of anaphyl reactions included urticarial, angioedema, itching, asthma and rhin three cases were classified as "severe reactions" requiring treatment an Considering only official data, the prevalence of allergic reactions was s (p < 0.001) in vaccinated patients with a history of severe allergy (3.8% to that in COVID-19 vaccinees from the general population (0.047%). * urticaria, angioedema, itching, asthma and rhinitis. Thirty-three cases were reactions" requiring treatment and medical support. No anaphylaxis was reco

Discussion
Within the catchment area of ASUGI Trieste, 706,573 doses of C were administered during the calendar year 2021 on a total populati residents. Vaccine hesitancy was immediately considered from the beg paign and an ATF was set up by ASUGI Trieste with the aim to evalu history of multiple allergies and those with previous reactions to COV our cohort, 269 subjects were assessed because they were considered lergic reaction, of whom 46 already had an allergic reaction following COVID-19 vaccine.
Out of 208 patients vaccinated against COVID-19, none develop severe allergic reactions, whereas 63 (30.3%), reported an allergic react  Table 4 reports the aggregated adverse and allergic reactions to dif vaccines in the general population of the Trieste-Gorizia catchment area, dose administered. The overall prevalence of allergic reactions was 0.04 doses administered in 2021) and only eight vaccinees were recorded in th surveillance system for adverse vaccine events. No cases of anaphylax reactions included urticarial, angioedema, itching, asthma and rhiniti three cases were classified as "severe reactions" requiring treatment and Considering only official data, the prevalence of allergic reactions was sig (p < 0.001) in vaccinated patients with a history of severe allergy (3.8% = to that in COVID-19 vaccinees from the general population (0.047%). * urticaria, angioedema, itching, asthma and rhinitis. Thirty-three cases were cl reactions" requiring treatment and medical support. No anaphylaxis was record

Discussion
Within the catchment area of ASUGI Trieste, 706,573 doses of CO were administered during the calendar year 2021 on a total population residents. Vaccine hesitancy was immediately considered from the begin paign and an ATF was set up by ASUGI Trieste with the aim to evaluat history of multiple allergies and those with previous reactions to COVID our cohort, 269 subjects were assessed because they were considered at lergic reaction, of whom 46 already had an allergic reaction following a COVID-19 vaccine.
Out of 208 patients vaccinated against COVID-19, none developed severe allergic reactions, whereas 63 (30.3%), reported an allergic reaction  Table 4 reports the aggregated adverse and vaccines in the general population of the Triestedose administered. The overall prevalence of alle doses administered in 2021) and only eight vaccin surveillance system for adverse vaccine events. reactions included urticarial, angioedema, itchi three cases were classified as "severe reactions" r Considering only official data, the prevalence of a (p < 0.001) in vaccinated patients with a history o to that in COVID-19 vaccinees from the general p * urticaria, angioedema, itching, asthma and rhinitis. reactions" requiring treatment and medical support. N

Discussion
Within the catchment area of ASUGI Tries were administered during the calendar year 202 residents. Vaccine hesitancy was immediately co paign and an ATF was set up by ASUGI Trieste history of multiple allergies and those with prev our cohort, 269 subjects were assessed because th lergic reaction, of whom 46 already had an allerg COVID-19 vaccine.
Out of 208 patients vaccinated against COV severe allergic reactions, whereas 63 (30.3%), repo  Table 4 reports the aggregated adverse and alle vaccines in the general population of the Trieste-Gor dose administered. The overall prevalence of allergi doses administered in 2021) and only eight vaccinees surveillance system for adverse vaccine events. No reactions included urticarial, angioedema, itching, three cases were classified as "severe reactions" requ Considering only official data, the prevalence of aller (p < 0.001) in vaccinated patients with a history of se to that in COVID-19 vaccinees from the general pop Table 4. COVID-19 vaccines administered in the genera catchment area) and adverse reactions reported by 31 Dec of adverse reactions out of total vaccine doses.  * urticaria, angioedema, itching, asthma and rhinitis. Thir reactions" requiring treatment and medical support. No a

Discussion
Within the catchment area of ASUGI Trieste, 7 were administered during the calendar year 2021 o residents. Vaccine hesitancy was immediately consid paign and an ATF was set up by ASUGI Trieste wit history of multiple allergies and those with previou our cohort, 269 subjects were assessed because they lergic reaction, of whom 46 already had an allergic r COVID-19 vaccine.
Out of 208 patients vaccinated against COVID severe allergic reactions, whereas 63 (30.3%), reporte  4 reports the aggregated adverse and allergic reactions to different COVID-19 the general population of the Trieste-Gorizia catchment area, according to the nistered. The overall prevalence of allergic reactions was 0.047% (=333/706,573 inistered in 2021) and only eight vaccinees were recorded in the Italian national e system for adverse vaccine events. No cases of anaphylaxis occurred, and ncluded urticarial, angioedema, itching, asthma and rhinitis events. Thirtywere classified as "severe reactions" requiring treatment and medical support. g only official data, the prevalence of allergic reactions was significantly higher in vaccinated patients with a history of severe allergy (3.8% = 8/208) compared OVID-19 vaccinees from the general population (0.047%).   angioedema, itching, asthma and rhinitis. Thirty-three cases were classified as "severe equiring treatment and medical support. No anaphylaxis was recorded.

VID-19 vaccines administered in
ion n the catchment area of ASUGI Trieste, 706,573 doses of COVID-19 vaccines inistered during the calendar year 2021 on a total population of 373,896 local Vaccine hesitancy was immediately considered from the beginning of the caman ATF was set up by ASUGI Trieste with the aim to evaluate patients with a multiple allergies and those with previous reactions to COVID-19 vaccines. In , 269 subjects were assessed because they were considered at higher risk of altion, of whom 46 already had an allergic reaction following a previous dose of vaccine. f 208 patients vaccinated against COVID-19, none developed anaphylaxis or rgic reactions, whereas 63 (30.3%), reported an allergic reaction, mainly urticar-): N = 1. Table 4 reports the aggregated adverse and allergic reactions to different COVID-19 vaccines in the general population of the Trieste-Gorizia catchment area, by dose administered. The overall prevalence of allergic reactions was 0.047% (=333/706,573 doses administered in 2021) and only 8 vaccinees were recorded in the Italian national surveillance system for adverse vaccine events. No cases of anaphylaxis occurred and reactions included urticarial, angioedema, itching, asthma and rhinitis events. Thirty-three cases were classified as "severe reactions" requiring treatment and medical support. Considering only official data, the prevalence of allergic reactions was significantly higher (p < 0.001) in vaccinated patients with history of severe allergy (3.8% = 8/208) compared to that in COVID-19 vaccinees from the general population (0.047%). * urticaria, angioedema, itching, asthma and rhinitis. Thirty-three cases were classified as "severe reactions" requiring treatment and medical support. No anaphylaxis was recorded.

Discussion
Within the catchment area of ASUGI Trieste, 706,573 doses of COVID-19 vaccines were administered during calendar year 2021 to a total population 373,896 local residents. Vaccine hesitancy was immediately considered from the beginning of the campaign and an ATF was set up by ASUGI Trieste with the aim to evaluate patients with a history of multiple allergies and those with previous reactions to COVID-19 vaccines. In our cohort, 269 subjects were assessed because they were considered at higher risk of allergic reaction, 46 of whom already had an allergic reaction following a previous dose of COVID-19 vaccine.
Out of 208 patients vaccinated against COVID-19, none developed anaphylaxis or severe allergic reactions, whereas 63 (30.3%) reported an allergic reaction, mainly urticarialwith wide difference by sex (16.5% in females vs. 9.1% in males)-followed by angioedema, erythema/itching and a few cases of asthma/oculo-rhinitis. Vaccine reactions were overall mild and in a third of cases immediate, i.e., developing within four hours of vaccination. However, the prevalence of allergic reactions in immunized patients with history of severe allergy (3.8%) was 80 times that of COVID-19 vaccinees from the general population (0.047%) of the same catchment area..
The higher proportion of allergic reactions to COVID-19 vaccines in females has already been reported 18 and is also consistent with the prevalence of allergic disease and particularly drug allergy in females [18][19][20][21][22][23]. Among the study group, food allergy was reported by 28.2% patients, drug allergy by 53.5% and 18.2% had a history of anaphylactic reaction to medications. Lower figures on food allergy (15.9%) and multiple drug allergy (32.9%) were found in a prospective cohort study conducted at Sheba Medical Centre (Tel Aviv, Israel) from 27 December 2020 to 22 February 2021 on 8102 patients with allergy history [20]. By contrast, the prevalence of food allergy in the general population is estimated to be <5% [14,21,24,25] and severe or multiple drug allergies is <1% [26].
In a study using US data from the Vaccine Adverse Event Reporting System (VAERS), out of 14,611 patients developing reactions, those with a history of allergy were more likely to develop immediate reactions after COVID-19 vaccination, especially vaccinees with history of anaphylaxis (OR 7.16; 95% CI 3.50-14.65) [13]. Likewise, in another analysis on VAERS data from 55 USA states between 14 December 2020 and 5 February 2021, out of 36,819,212 doses of COVID-19 vaccines administered as of 5 February 2021, the incidence of anaphylaxis among 12,630 COVID-19 vaccine recipients was 4.2 per million doses, with a risk of 1.85% (95% CI: 1.44%; 2.25%) among those with previous allergies and 7.91% (95% CI: 3.33%; 12.49%) among those with history of anaphylaxis [27]. In a further online survey on 1808 Polish respondents, 1707 of whom received two doses of Comirnaty, whilst reactions were far more likely after the second dose and among high-risk allergic patients, the majority of these reactions were mild and did not preclude the completion of the vaccination cycle [28].
In the present study, in case of a previous reaction to multiple drugs containing PEG or PS80 and intolerance to any drugs containing the latter two preservatives, skin tests were performed (N = 18 for PEG and N = 3 for PS80 and macrogol), finding only one positive reaction to PS80 in a patient with history of generalized reaction to PEG (5.6%). The utility of skin tests against the latter two preservatives is debatable although recommended by the Italian and International Societies for Allergic Diseases [7,11,29,30]. However, in a US study on 80 consecutive patients reporting allergic reactions to m-RNA COVID-19 vaccines, skin testing did not influence the tolerance against the second dose, which was well-received by the majority of vaccinees (N = 70) [31]. However, it is worth mentioning that COVID-19 vaccines contain several further excipients rarely inducing allergy, such as aluminum hydroxide, disodium EDTA, Matrix M™, Matrix-A and Matrix-C particles [32]. The latter excipients are not only included in vaccine preparations but can also be present in various everyday items, which could potentially sensitize users [33].
In our study, high-risk allergic patients were monitored for an extended time (at least 1 h) following vaccination and no cases of anaphylaxis were observed.
Allergic reactions to COVID-19 vaccines can be early, delayed or late [34,35]. Rapid reactions are mediated by IgE antibodies against a vaccine component, or via another mechanism activating mast cells [20] as a complement activation-related pseudoallergy (CARPA), already described for liposomes [29]. Other reactions include late onset of urticaria, eczema, erythema and itching [36,37]. Late-onset or delayed reactions following COVID-19 vaccination may include urticaria, eczema, erythema or itching hours to days after immunization, or late-onset local injection site reactions or swelling at the site of dermal fillers, developing several days after immunization [35][36][37].
In our study, 8.7% of patients reporting allergic reactions (mainly urticaria and angioedema) within 4 h after immunization were treated with antihistamine and cortisone, whereas 21.6% developed reactions (mainly urticarial) >4 h after vaccination. Likewise, in a Belgian survey by telephone interviews, 25 (11.3%) immediate reactions were observed among 221 doses of m-RNA or adeno-viral vector vaccines administered to 196 patients at risk of immediate hypersensitivity reactions at the university hospital of Leuven (Belgium) [23]. By contrast, in the above Israeli study from Sheba Medical Centre in Tel Aviv, only 9 (2%) out of 429 highly allergic patients developed immediate reactions, three (0.7%) of which were anaphylactic [20].
In the present study, only 8 (3.8%) patients had a relevant reaction according to the Italian Database for Adverse Event Following Immunization, whereas for other patients adverse reactions were mild and therefore were neglected.
The prevalence of skin reactions was 21.6% in the present study, a rather high figure not far from that (15%) reported for skin eruption and itching in the above Israeli study from Sheba Medical Centre [20]. Ieven et al. [23] in 2022 also reported that 13.2% of late reactions had mast cell activation-like symptoms. However, the latter reactions were mild and self-limited in the present study.

Strengths and Limitations
A strength of our study is the thorough and in-depth clinical assessment and follow up of each patient, thereby maximizing a reliable detection of allergic reactions to COVID-19 vaccination. Investigating vaccinees over the phone allowed us to identify symptoms in a detailed fashion, finding a very low incidence of severe reactions and a rather high incidence of mild and late allergic symptoms following immunization. Some published studies on the reactions to COVID-19 vaccines rely on health registries collecting adverse effects rather than actually following up vaccinees individually [2,20,38].
However, the present study also has some limitations. Patients reported allergic reactions after vaccination during a telephone interview, an approach potentially affected by recall bias and an overestimation of the reactions, since allergic people also tend to report very mild side effects after vaccination (nocebo effect). However, it is also well known that the Database for Adverse Event Following Immunization underestimates reactions because only significant or severe reactions tend to be reported.
Only in case of suspicion of allergy to PS80 or PEG skin tests were performed in the present study, hence a limited number of patients were tested, with only one subject resulting positive for PS80. As already mentioned, the utility of these skin tests and the relevance of sensitization to these two excipients is still under debate [31].
Furthermore, although skin tests against vaccines themselves were not performed, the assessment of allergy to COVID-19 vaccines by intradermal testing with the entire vaccine should be systematically considered, offering tailored immunization protocols (e.g., alternative vaccine, premedication, desensitization, etc.) to patients at high risk of allergic reactions [39].

Conclusions
The prevalence of mild yet late allergic reactions in immunized patients with a history of severe allergy was 80 times that in COVID-19 vaccinees' from the general population. The use of antihistamine as premedication, to be continued for one week following immunization, may be considered to prevent these adverse reactions in selected patients appropriately screened.

Institutional Review Board Statement:
The study was conducted according to the guidelines of the Declaration of Helsinki and approved by the ethical committee of Friuli-Venezia Giulia (CEUR-2020-Os-072) on 16/04/2020. Informed Consent Statement: Patient consent was waived since, according to Italian privacy law (Legislative Decree 101/2018, D.Lgs 101/2018), patients' data routinely collected by the Italian National Health Service can be used for scientific purposes within the scope of approved studies/protocols, provided sensitive information is anonymized.

Data Availability Statement:
The datasets generated and analyzed during the current study are not publicly available, since they were purposively collected by the authors for the present study, but they may be available from the corresponding author on reasonable request.