The World Health Organization (WHO) thinks that vaccinated people may need a ‘booster shot’ every two years to maintain their protection against the coronavirus and its variants. For vulnerable groups, such as the elderly, this could be necessary every year. In the worst-case scenario, that would apply to the entire population.
Those estimates are in an internal document that the Reuters news agency has seen. It will be discussed Thursday in a meeting of the international organization Gavi, which, together with the WHO, leads the Covax program to get vaccines to poorer countries. These periods are subject to change.
Vaccine makers Pfizer/BioNtech and Moderna have repeatedly stated that additional injections will be necessary after the first two injections, but no hard evidence has yet been produced.
The preliminary document states that new variants will continue to emerge, which would require people to have a “vaccine update.” It goes on to say that 12 billion doses of vaccine will be produced next year in the most likely scenario, slightly more than the 11 billion manufacturers expect so far.
However, problems are expected in the production and approval of modified vaccines, as a result of which production may lag significantly. The document does not clarify whether certain vaccine technologies are favoured, as the EU has done. The country bloc mainly opts for the so-called mRNA technique that Pfizer/BioNTech and Moderna use at the expense of AstraZeneca and Janssen of Johnson & Johnson.
Around 2.5 billion doses have now been administered worldwide. In rich countries, sometimes half of the population has already been vaccinated (the first time), but it is only 1 in 100 or even less in many other countries. That gap could widen even further if the need for booster shots pushes poor countries to the rear, the fear is.
In an optimistic scenario, all vaccines currently in the pipeline will receive approval, and production could be ramped up to 16 billion doses per year, which could be distributed fairly around the world. Boosters would not be necessary because the existing vaccines provide long-lasting and powerful protection.