BA.4/BA.5 Omicron Subvariants Over 4 Times More Resistant to mRNA
Omicron subvariants are resistant to mRNA. These mutations have clinical relevance as the target of neutralising antibodies. This variant has three mutations in the membrane protein and six mutations in the nucleocapsid protein. Some of these mutations have already been observed in other variants.
Omicron subvariants are more resistant to mRNA
Vaccines against BA.4/BA.5 Omicron subvariants are more effective against these viruses than against other subvariants. They have higher antigenicity and cross-variant neutralization capacity than other subvariants. These antibodies were also more effective than those against BA.1.
This finding may have significant implications for current strategies for the containment of the SARS-CoV-2 pandemic. The development of new variants of this virus could require more urgent public health interventions to limit transmission and reduce morbidity. This review article reviews the evolution of Omicron variants and the neutralisation capacity of sera against these viruses.
The emergence of new variants has raised the question of whether the virus will be able to escape the immune system. One large-scale study from South Africa showed that Omicron subvariants are more resistant than other variants. The number of daily new reinfections with this variant was much higher than expected. In addition, the hazard ratio of reinfection was much higher than the hazard ratio for primary infections. However, the study authors cautioned that the findings were epidemiological-based and that further laboratory neutralisation tests are needed to confirm the finding.
Omicron BA.1-adapted bivalent vaccine elicited superior immune response against the Omicron BA.1 subvariant
In a recent study, a bivalent vaccine containing the Omicron BA.1 variant was able to elicit a higher immune response than a placebo-treated control group. The bivalent vaccine also had an excellent safety profile. However, there are some caveats that should be kept in mind when comparing results across different trials. For instance, differences in the timing and the use of neutralization assays may have an impact on results. Nevertheless, recent data from the Omicron-adapted bivalent vaccine demonstrate superior immunogenicity and an acceptable safety profile.
The data obtained from the bivalent COVID-19 vaccine have been shared with regulators and Pfizer. In addition to the original strain mRNA component, the bivalent vaccine also contained the mRNA component common to the omicron variant BA.4 and BA.5 lineages, which have caused the majority of COVID-19 cases in the U.S. and are expected to circulate again this winter.
Omicron BA.4/BA.5 subvariants have higher infectivity than Wuhan-Hu-1 and Delta variants
These findings indicate that BA.4/BA.5 subvariants of Omicron are more infectious than the Wuhan-Hu-1 and Delta variants. The reason for this is not fully understood, but the BA.4 subvariant has been implicated in an increasing number of infections in Europe. The Deltacron variant has been implicated in increased disease severity and reduced vaccine efficacy. Therefore, ongoing surveillance of this virus is recommended.
These SARS-CoV-2 strains differ in several amino acid sequences. The Omicron strain differs from the Delta strain in the RBD, a region that interacts with the viral ACE2 receptor and is a primary target of neutralizing antibodies. Similarly, the BA.1 and BA.2 S proteins share twenty amino acid changes, 12 of which occur in the RBD.
While the BA.2 subvariant is predominant worldwide, BA.4/BA.5 subvariants are the leading cause of infections in many countries. The L452R mutation reduces the binding of ACE 2 and may also give the strain a greater propensity toward lung infections.