SARS-CoV-2 Variant and Vaccines Development

Dear Colleagues,

Several variants of SARS-CoV-2 have emerged and newer variants and mutants / strains are continuously emerging owing to this rapidly evolving virus and gaining higher mutations facilitating waves of surging COVID-19 cases amid the ongoing COVID-19 pandemic. Various variants of concerns (VOCs) and variants of interests (VOIs) have emerged, and among these Alpha, Beta, Gamma, Delta and Omicron (VOCs) are of major concerns with regards to adverse public health implications. Delta and Omicron variants possess high transmissibility and can overpower vaccine induced immunity and antibodies-based therapeutics resulting into breakthrough infections in vaccinated people and recovered patients as well reinfection cases are on rise. More recently, different lineages of Omicoron (BA.1/BA.1.1, BA.2 or BA.3) have been recognized as well as recombinant variants of SARS-CoV-2 with Omicron and Delta combinations have been reported (XD, XE, XF), which reflects the continuous evolution of the pandemic virus and its variants. Several repurposed and antiviral drugs have been used for emergency purposes, however any optimal drug of choice to treat COVID-19 patients is still awaited. Booster doses of vaccines are being recommended to increase the protective immunity levels in vaccinated individuals for safeguarding from emerging variants, especially VOCs.  

For tackling COVID-19 pandemic, researchers across the globe made very high efforts which lead to development of vaccines within one year, and different vaccines were subsequently rolled out across several countries with the availability of Moderna, Pfizer/BioNTech, AstraZeneca and other vaccines, utilizing different vaccine platforms. However, recent reports have show that variants such as Delta and Omicron show immune evasion and antibody escape mechanisms for mostly all the kinds of vaccines, resulting in rise in COVID-19 cases and breakthrough infections. Besides, probable risks are always there for emergence of any newer variants that might gain both higher transmission ability and more lethality. Such adverse scenario of lesser protection being rendered by existing COVID-19 vaccines have forced researchers and health agencies to rethink for updating and modifying the current vaccines as well as design newer vaccines to combat SARS-CoV-2 and emerging variants. 

Development of advanced vaccines that could provide a broad range of protection against all the emerging variants or the upcoming variants of SARS-CoV-2 is the need of the present times to put a halt on the pandemic. Advances in developing newer vaccines / new generation vaccines need to focus on designing variant-specific vaccines, multivariant (multiple antigen-based) vaccines, mutation-proof vaccines, pancoronavirus and universal vaccines, and multitopevaccines that would be highly efficacious to tackle multiple emerging SARS-CoV-2 variants and variants of future by counteracting the immune escape properties and render adequate protection against COVID-19. Exploring various advanced techniques and platforms, the development of CRISPR-based vaccines, artificial intelligence-based vaccines, immunoinformatics- and immunomics-based vaccines, nanotechnolology based vaccines / nanovaccines, nucleic acid-based and protein subunit-based vaccines, and cytotoxic T-cell-based vaccine should be given due emphasis. Several COVID-19 intranasal vaccines are also being developed, which could elicit both systematic immunity and strong mucosal immunity that aid in inhibiting the virus at mucosal levels (nasal cavity, lungs), prevent viral replication, reduce virus shedding, thus preventing its further transmission and spread. 

To achieve a more extensive understanding of recent scientific knowledge, current trends and advances being made in vaccine development against SARS-CoV-2 and its emerging variants, this Special issue is focused on the recent scientific and technical progresses made in this field along with future prospects. Based on your extensive knowledge and experience, we invite you to contribute with an original report, original observation or review, on recent advances and futuristic vision in developing better vaccines to tackle SARS-CoV-2 and emerging variants.

Dr. Kuldeep Dhama
Dr. Chiranjib Chakraborty
Guest Editors

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