Vaccination-induced response to Omicron subspecies neutralization

In a recent study posted on medrex sib*Preprint server, researchers have identified Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Omicron variant subvariants (BA.1, BA.1.1, BA.2, BA.2.12.1, BA.3 , BA.4/5) Neutralization. They also performed a comparative assessment of the cross-neutralizing response of the Omicron subvariant compared to the Wuhan-Hu-1 strain (prototype). antigen.

Vaccination is threatened by the constant evolution of Omicron and the consequent emergence of subvariants with higher infectivity and immune evasion Effectiveness It is accompanied by a reduction in cross-neutralizing reactions with vaccination. In vitro studies We report significantly lower Ab (antibody) function against the omicron spike (S) protein among convalescent and vaccinated individuals with a history of non-omicron infection.

About research

In the current study, researchers evaluated the Omicron subvariant neutralization response induced by coronavirus disease 2019 (COVID-19) vaccination.

Databases such as PubMed, medRxiv, and bioRxiv were searched between 26 November 2021 and 25 July 2022 to assess neutralizing antibody (nAb) responses after COVID-19 vaccination against Omicron subvariants Research has been done. This study was ancillary to a literature review. This included only published studies or preprints evaluating nAb responses to one or more Omicron subvariants induced by the World Health Organization (WHO)-approved COVID-19 vaccine. We also analyzed samples obtained within 6 months of the most recent vaccination.

Data include neutralization assay, reference SARS-CoV-2 strain, sample size, vaccination dose, type of vaccination, time from most recent vaccination to sample collection, Wuhan-Hu-1 strain nAb titer, and Obtained in Omicron variants and samples. Detectable nAb titers or proportions of prototype strains and each subvariant.

Studies were excluded if a surrogate neutralization assay was used, immunosuppressed individuals were sampled, and the study cohort consisted of preselected low- or high-responders. Her >20% study of individuals with hybrid (natural and vaccinated) immunity was also excluded. We evaluated the median percent reduction in Omicron subvariant nAb titers compared to each other and the Wuhan-Hu-1 strain, and calculated the median percentage of responders per strain.

result

A total of 6,318 study abstracts were screened, of which only 213 studies were eligible for full-text review, of which 153 were included in the final analysis. Approximately 80% (n=122 studies) of studies assessed fold reductions of Omicron subvariants associated with the Wuhan-Hu-1 strain, and 22% (n=33) of studies assessed Omicron BA.1 Evaluating fold reductions in other Omicron subvariants, 88% (n=135) of the studies provided data on the percentage of response to one or more Omicron subvariants.

Among the included studies, the subvariant-specific reduction in nAb titers for the Wuhan-Hu-1 strain after primary vaccination with COVID-19 ranged from a 4.2-fold reduction in Omicron BA.3 to Omicron BA. showed wide variation, up to 22 times of 3. Among boosted individuals, the fold reduction was comparable for all Omicron subvariants (between 6- and 7-fold) except for the Omicron BA.4/5 subvariant (13-fold). did.

nAb titers induced after primary and booster vaccinations were higher in all Omicron subvariants except BA.4/5, which had a higher fold reduction (2-fold higher) compared to Omicron BA.1 It was the same. After the first vaccination with COVID-19, the percentage of responders per Omicron subvariant was lower (34% to 57%) compared to the Wuhan-Hu-1 strain (96%). Still, it increased after booster vaccination (between 85% and 93%).

Of the included studies, 82% (n=125 studies) provided data on fold reductions of 1 or more omicron subvariants associated with the Wuhan-Hu-1 strain. After the first vaccination of COVID-19, the reduction rates associated with the Wuhan-Hu-1 strain were greater for all Omicron subvariants, ranging from 4.2-fold for Omicron BA.3 to 22-fold for Omicron BA.4/BA. rice field. 5 subvariant and was the largest reduction (42.5-fold) with his protein subunit-based COVID-19 vaccine observed across all vaccine platforms.

The fold reduction to Omicron BA.1 associated with the Wuhan-Hu-1 strain was higher for messenger ribonucleic acid (mRNA) COVID-19 vaccines than for vector-based vaccines (12-fold) and inactivation (21-fold ) COVID-19 vaccine (11x). Moreover, heterologous COVID-19 vaccination strategies involving mRNA vaccines had a greater rate of reduction (22-fold).

nAb after booster vaccination titer The fold reduction of Omicron subvariants associated with the Wuhan-Hu-1 prototype was not as pronounced as that observed after primary vaccination, ranging from 6-fold for Omicron BA.2 to 13-fold for Omicron BA.4/5. did. Median reductions in Omicron BA.1 nAb by vector-, inactivated, and protein-based vaccines were 8-fold, 9-fold, 10-fold, and 6-fold compared to mRNA vaccines . However, the results were uneven.

Overall, the results of this study showed that the fold reduction in nAb titers of Omicron subvariants associated with the Wuhan-Hu-1 strain varied considerably after primary vaccination with COVID-19, except for Omicron BA.4/5. showed that it was similar after booster vaccination. Which ratio was higher? Findings indicated that vaccine efficacy was likely to be low for his Omicron subvariant, especially his BA.4/5.

*Important Notices

medRxiv publishes non-peer-reviewed, preliminary scientific reports and should not be considered conclusive, to guide clinical practice/health-related actions, or to be treated as established information .