The World Health Organisation (WHO) has warned against the repeat use of original Covid-19 vaccines as booster shots and said the strategy is “unlikely to be appropriate or sustainable” in the fight against emerging variants.
“A vaccination strategy based on repeated booster doses of the original vaccine composition is unlikely to be appropriate or sustainable,” the WHO Technical Advisory Group on Covid-19 Vaccine Composition (TAG-Co-VAC) said in a statement on Tuesday.
The 18-member expert task force assessing the performance of Covid vaccines has also asked for new jabs that can provide better protection against the transmission of the virus.
“The TAG-Co-VAC considers 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,” said the statement.
Simply providing fresh jabs of existing vaccines was not the best way to fight the pandemic, the panel pointed out.
Vaccines should be based on variants “that are genetically and antigenically close to the circulating Sars-CoV-2 [the scientific name for the novel coronavirus] variant(s),” the TAG-Co-VAC explained.
The panel said it would consider a change in the composition of vaccines.
Existing vaccines were less effective in preventing symptomatic Covid disease in people who contracted the Omicron variant of the virus, according to preliminary data.
Protection against severe disease, however, “is more likely to be preserved”.
In addition to protecting people against severe disease and death, Covid vaccines “need to be more effective in protection against infection thus lowering community transmission and the need for stringent and broad-reaching public health and social measures,” the WHO said.
The vaccines should also “elicit immune responses that are broad, strong, and long-lasting in order to reduce the need for successive booster doses.”
Meanwhile, vaccine makers should generate and provide data on performance of existing and Omicron-specific Covid vaccines, the expert task force said.
This should include the “breadth, magnitude, and durability of humoral and cell mediated immune responses to variants through monovalent and/or multivalent vaccines,” it added.
The data will go on to help TAG-Co-VAC when changes to vaccine compositions may be required.
The panel noted the global urgency of prioritising primary vaccination for high-groups as opposed to booster shots in some countries.
“In practical terms, while some countries may recommend booster doses of vaccine, the immediate priority for the world is accelerating access to the primary vaccination, particularly for groups at greater risk of developing severe disease,” the statement said.
Omicron is unlikely to be the last Variant of Concern as the evolution of the virus is expected to continue, the panel pointed out.