The WHO said its expert group Messenger evaluated limited data from seven studies for second booster doses of the RNA vaccine, saying there was not enough data to prove their effectiveness in young, healthy individuals.
“Among those who are most at risk of serious illness or death … the added benefit of an extra booster dose of the mRNA vaccine can be guaranteed,” the WHO said, acknowledging that giving people a second booster dose could be a logical or other challenge in some countries. While many rich countries have vaccinated more than 70% of their population, poorer countries have vaccinated less than 16%.
Last year, the WHO repeatedly criticized rich countries for giving booster doses and called for a moratorium on the practice, saying boosters were unnecessary for healthy people. After dozens of countries began offering booster doses, the agency reversed its advice late last year amid widespread outbreaks of the contagious Omicron variant.
Some health experts have warned that countries launching additional booster campaigns before giving single shots to the weakest people in developing countries could reduce the world’s supply of the COVID-19 vaccine.
The U.S. Food and Drug Administration recommended in March that Americans 50 and older be eligible for a second Covid-19 booster shot while the European Medicines Agency cleared only a second booster dose for those 80 and older.
In the wake of the continued proliferation of Omicron and its subvariant, the WHO and others have continued to call for accelerated vaccine promotion.
“We see that those who have been vaccinated have a significantly lower risk of serious disease and death,” said Maria Van Kerkhov, head of WHO’s COVID-19, warning against the false notion that Omicron is light. “We have the solution because we have the vaccine,” he said.
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