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Vaccine strategy based on booster doses of same composition not sustainable: WHO

Vaccine strategy based on booster doses of same composition not sustainable: WHO

The TAG-CO-VAC said that COVID-19 vaccines that have high impact on prevention of infection and transmission, in addition to the prevention of severe disease and death, are needed and should be developed. 

COVID-19 vaccine booster doses COVID-19 vaccine booster doses

Amid a global demand for booster shots for protection against the Omicron variant, the World Health Organisation (WHO) has warned that a vaccination strategy based on repeated booster doses of the original vaccine composition is unlikely to be appropriate or sustainable. 
 
The apex UN public health agency has urged vaccine manufacturers to generate and provide data on performance of current and Omicron-specific COVID-19 vaccines and also make changes in the composition of the current vaccines for long lasting protection.
 
WHO has also established the Technical Advisory Group on COVID-19 Vaccine Composition (TAG-CO-VAC) to review and assess the public health implications of emerging SARS-CoV-2 Variants of Concern (VOC) on the performance of COVID-19 vaccines and to provide recommendations to WHO on COVID-19 vaccine composition, as needed.
 
The panel on Tuesday said that it is considering the strain composition of COVID-19 vaccines, and encouraging vaccine developers to gather data on a small scale on the breadth and magnitude of immune response for monovalent and multivalent vaccines against VOCs – this data would then be considered in a broader decision-making framework on vaccine composition by the TAG-CO-VAC.
 
“With near- and medium-term supply of the available vaccines, the need for equity in access to vaccines across countries to achieve global public health goals, programmatic considerations including vaccine demand, and evolution of the virus, a vaccination strategy based on repeated booster doses of the original vaccine composition is unlikely to be appropriate or sustainable,” the WHO said in a statement.
 
The TAG-CO-VAC said that COVID-19 vaccines that have high impact on prevention of infection and transmission, in addition to the prevention of severe disease and death, are needed and should be developed. 
 
“Until such vaccines are available, and as the SARS-CoV-2 virus evolves, the composition of current COVID-19 vaccines may need to be updated, to ensure that COVID-19 vaccines continue to provide WHO-recommended levels of protection against infection and disease by VOCs, including Omicron and future variants,” the WHO said.
 
The panel has said that new COVID-19 vaccines need to be based on strains that are genetically and antigenically close to the circulating SARS-CoV-2 variant(s) and elicit immune responses that are broad, strong, and long-lasting in order to reduce the need for successive booster doses.

The panel has recommended vaccine manufacturers to consider a monovalent vaccine that elicits an immune response against the predominant circulating variant(s), although this option faces the challenge of the rapid emergence of SARS-CoV-2 variants and the time needed to develop a modified or new vaccine. The panel has also recommended a multivalent vaccine containing antigens from different SARS-CoV-2 VOCs; or a pan SARS-CoV-2 vaccine – a more sustainable long-term option that would effectively be variant-proof.
 
In the interim, the TAG-CO-VAC asked the COVID-19 vaccine manufacturers to generate and provide data on performance of current and Omicron-specific COVID-19 vaccines, including the breadth, magnitude, and durability of humoral and cell mediated immune responses to variants through monovalent and/or multivalent vaccines. These data will be considered in the context of the framework mentioned above to inform the TAG-CO-VAC decisions when changes to vaccine composition may be required, the WHO said.

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