Getting a Pfizer booster jab five months after a second dose reduces a person’s risk of hospitalisation with Covid by 93 per cent, according to new research in The Lancet.
The study from the Clalit Research Institute in Tel Aviv and Harvard University in the US is the first nationwide analysis of booster jab effectiveness and involved 1.5 million Israelis.
Half of these people got a booster, while the other half had not yet received one.
Israel was a pioneer in the distribution of vaccines at the start of 2021, getting a jab in the arm of half of its population by the end of February. But by the time a fourth wave hit the nation in summer, there was some waning of vaccine-induced immunity.
Data from the study show that a person’s risk from Covid in the week after getting a booster is much lower than someone who is only double-jabbed.
“Vaccine effectiveness… was estimated to be 93 per cent for admission to hospital, 92 per cent for severe disease, and 81 per cent for Covid-19-related death,” the researchers wrote.
The protection from the fresh inoculation was found to be unaltered by the recipient’s age, overall health or age.
But while a booster did drastically reduce the threat of Covid relative to someone who does not get their booster, the absolute risk from Covid is still tiny for the double-jabbed.
For example, of the 750,000 people who did get a booster, there were just 44 Covid deaths among the double-jabbed, compared to seven for the booster group.
Only 29 people who got a booster went on to be admitted to hospital due to Covid.
A paper prepared by the Effectiveness Expert Panel shows that between three and six months, a double-vaccinated person who received the Oxford/AstraZeneca jab is still 85 per cent protected against hospitalisation compared to an unvaccinated individual. For death, the reduction in risk is 90 per cent.
Pfizer performed slightly better, with two doses giving 95 per cent protection against both death and hospitalisation.
“These results show convincingly that the third dose of the vaccine is highly effective against severe Covid-19-related outcomes in different age groups and population subgroups, one week after the third dose,” said Prof Ran Balicer, the senior author of the study.
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