Rich countries now have an approved updated Covid-19 booster shot for specific Omicron sub-variants.
The variant-specific vaccines (known as bivalent boosters) were manufactured by Pfizer-BioNTech and Moderna and are now available for use in the US after getting authorisation from the US Food and Drug Administration (FDA). They become the first authorised bivalent boosters for Covid-19 and its approval has been recommended by the Centres for Disease Control and Prevention (CDC).
“The updated Covid-19 boosters are formulated to better protect against the most recently circulating ... variant. They can help restore protection that has waned since previous vaccination and were designed to provide broader protection against newer variants. This recommendation followed a comprehensive scientific evaluation and robust scientific discussion,” CDC Director Rochelle Walensky said in a statement.
“The FDA has been planning for the possibility that the composition of the Covid-19 vaccines would need to be modified to address circulating variants. We sought input from our outside experts on the inclusion of an omicron component in Covid-19 boosters to provide better protection. We have worked closely with the vaccine manufacturers to ensure the development of these updated boosters was done safely and efficiently.
The FDA has extensive experience with strain changes for annual influenza vaccines. We are confident in the evidence supporting these authorisations,” said FDA Center for Biologics Evaluation and Research Director Peter Marks. The FDA said in a statement that the bivalent Moderna Covid-19 vaccines will be administered as a single booster dose in people aged 18 and above. The bivalent Pfizer-BioNTech Covid-19 has been authorised for use as a single booster dose in people aged12 and older.
The FDA says those eligible for the bivalent shots have to have had at least two months since they either completed primary vaccination or received the most recent booster dose with any authorised or approved Covid-19 vaccine.
The two sub-lineages, BA.4 and BA.5 were first discovered in South Africa and scientists said they were likely drivers of the now flattened sixth wave of Covid-19. The two were also the first culprits of escaping immunity derived naturally from the body as well as vaccines and their boosters.
“Although vaccines are effective at preventing severe disease, they are less effective at preventing transmission, particularly of the Omicron sub lineages,” said a study published in July this year at the scientific journal, Cell.
“We report a greater escape from the neutralisation of BA.4 and BA.5 compared with BA.1 and BA.2. It is clear that the Omicron lineage, particularly BA.4 and BA.5, has escaped or reduced the activity of antibodies developed for clinical use, with most antibodies showing complete knockout of activity,” revealed the research.