In a recent study published in medRxiv* Prepress server, researchers summarize existing data on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sub variant of the Omicron (BA.1, BA.1.1, BA.2, BA.2.12.1, BA. 3, and BA.4/5) neutralization. They also performed a comparative evaluation of the cross-neutralization responses of the Omicron sub-variables compared to the Wuhan-Hu-1 strain (prototype) antigen.
The continued development of Omicron and the consequent emergence of sub-variants with higher susceptibility to infection and immune evasion has threatened vaccination. effectiveness With a decrease in vaccination-induced cross-neutralization responses. In vitro studies reported significantly decreased AB (antibody) function against the Omicron spike (S) protein between vaccinated and vaccinated subjects with a previous history of non-Omicron infection.
In this study, researchers evaluated the responses of nulling variants caused by coronavirus 2019 (COVID-19) vaccines.
Databases such as PubMed, medRxiv and bioRxiv were searched between November 26, 2021 and July 25, 2022, for studies evaluating post-COVID-19 vaccination responses that neutralize Ab (nAb) responses to Omicron subvariants. The study was secondary to a literature review. It included only published studies or prior publications evaluating nAb responses to the ≥1 Omicron subvariant induced by the WHO-approved COVID-19 vaccine. It also analyzed samples obtained less than 6 months after the last vaccination.
Data were obtained for the neutralization assay, reference SARS-CoV-2 strain, sample size, vaccination doses, type of vaccination, duration between most recent vaccination and sample collection, nAb titers for the Wuhan-Hu-1 strain, Omicron subvariables and sample lineage with a resizable nAb titer. For discovery or prototyping strain and each sub-variable.
Studies were excluded if alternative equivalence assays were used, immunosuppressed individuals were sampled, and previously selected low or high responding study groups formed. Studies of more than 20% of individuals with hybrid immunity (natural infection and immunization) were also excluded. The mean fold decrease in the Omicron subvariant nAb titer compared to each other and the Wuhan-Hu-1 strain was evaluated, and the effector ratios were averaged in terms of stress.
In total, abstracts from 6318 studies were examined, of which only 213 studies were eligible for full-text review, of which 153 were considered for final analysis. About 80% (n = 122 studies) studies assessed fold reductions for Omicron subvariants with respect to the Wuhan-Hu-1 strain, 22% (n = 33) studies assessed fold reductions for other Omicron subvariants related to Omicron BA.1, and 88% (n = 135) provided data on the percentage of responses to the ≥1 Omicron subvariant.
Among the included studies, post-primary vaccination for COVID-19, variable-wise reductions in nAb titers with respect to the Wuhan-Hu-1 strain showed wide differences, from 4.2-fold for Omicron BA.3 to 22-fold for Omicron BA.4/ 5. Among the reinforced individuals, fold reductions were comparable for all Omicron subvariants (between sixfold and sevenfold), except for the Omicron BA.4/5 subvariant (13fold).
The induced nAb titers after the primary and booster vaccinations were similar for all Omicron subvariants, except for BA.4/5 where the fold reductions were higher (two-fold higher) with respect to Omicron BA.1. The percentages of Omicron-type responders were lower after the initial COVID-19 vaccination (between 34% and 57%) compared to the Wuhan-Hu-1 strain (96%). However, it increased after booster vaccinations (between 85% and 93%).
Of the included studies, 82% (n = 125 studies) provided data on fold reductions of the 1 Omicron variant in relation to the Wuhan-Hu-1 strain. Post-primary COVID-19 vaccines, fold reductions with respect to the Wuhan-Hu-1 strain were significant for all Omicron subvariants, ranging from 4.2-fold for Omicron BA.3 to 22-fold for Omicron BA.4/BA.5 subvariants and observed across all Vaccine platforms, with the largest decrease (42.5-fold) by protein-based COVID-19 vaccines.
The fold reductions against Omicron BA.1 with respect to the Wuhan-Hu-1 strain were higher (21-fold) higher (21-fold) for the COVID-19 messenger ribonucleic acid (mRNA) vaccines than with the vector-based (12-fold) and inactivated (11-fold) COVID-19 vaccines. Moreover, folded reductions of heterogeneous vaccination strategies for COVID-19 that include mRNA vaccines were significant (22-fold).
Subsequent vaccinations, incorrect caliber The fold reductions of the Omicron sub-variables with respect to the Wuhan-Hu-1 prototype were not as prominent as those observed after initial vaccinations and ranged from six-fold for Omicron BA.2 to 13-fold for Omicron BA.4/5. The average fold decrease was nAb eightfold, ninefold, tenfold, and sixfold relative to Omicron BA.1 by vector-based, inactivated and protein-based vaccines compared to mRNA vaccines; However, the results were heterogeneous.
Overall, the study results showed that reductions in nAb titer for Omicron subvariants with respect to the Wuhan-Hu-1 strain varied significantly after initial COVID-19 vaccinations but were similar after booster vaccinations, with the exception of Omicron BA.4/5, for That cuts were fold higher. The results showed that vaccine efficacy is likely to be lower for omicron subvariants, especially for BA.4/5.
medRxiv publishes preliminary scientific reports that are not subject to peer review, and therefore should not be considered conclusive, guide clinical practice/health-related behavior, or be treated as established information.