A third dose of the Pfizer vaccine provides “excellent” immunity, the first full trial has shown, as Boris Johnson suggested older people should be able to get boosters sooner than currently allowed.
The prime minister piled pressure on vaccines chiefs to change their advice and let people have boosters less than six months after their second dose, as a study showed an additional jab raises protection by a further 95 per cent.
In the study of 10,000 people, those who received a third injection of the Pfizer vaccine almost a year after their first two saw protection against symptomatic infection soar compared with those who had had just two doses.
An earlier study, looking at real world data from Israel, found a similar boost in protection against serious illness.
This means that any waning of the first two doses is more than compensated for by the third, scientists said. Since its early introduction of a booster programme, Israel has seen a steady fall in its case rates and hospital admissions.
Professor Jeremy Brown, a member of the Joint Committee on Vaccination and Immunisation (JCVI), said: “These two studies show the booster jab provides excellent protection against both mild and more serious Covid-19 infections so should both reduce the infection rates in the community and the pressure on hospital services.”
The JCVI advised that people should wait six months after their second dose before having a booster to ensure that immunity is maintained through the winter months.