Pfizer jab lowers infection risk by 93% in adolescents, Israelis find

The launch of vaccinations for 12- to 17-year-olds on Wednesday coincided with new findings that the Pfizer/BioNTech vaccine significantly decreases symptomatic Covid-19 in adolescents.

The three-month study in Israel, an early leader in Covid-19 vaccinations, involved almost 189,000 adolescents, equally split between vaccinated and unvaccinated.

The study, between July and September, coincided with Israel’s fourth wave of Covid-19 infections, during which the Delta variant was the dominant strain — as it is in SA.

Between two and three weeks after having a Pfizer jab — one of two being used in SA — the risk of symptomatic Covid-19 was 57% lower in vaccinated adolescents.

Between a week and three weeks after the second Pfizer jab, the risk was 93% lower.

For now, based on advice from the vaccine ministerial advisory committee, South African teenagers are receiving a single Pfizer jab.

If you still have not taken up your offer to be vaccinated, I would encourage you to do so based on the clear benefits it offers.

—  Prof Aziz Sheikh, from the University of Edinburgh’s Usher Institute

Health minister Joe Phaahla said in a few instances there had been short-lived transient myocarditis (inflammation of the heart muscle) after two doses. 

“The timing of the second dose will be informed by further information on this rarely observed side effect which has no permanent risk,” he said.

The Israeli study’s senior author, Prof Ran Balicer of Clalit Research Institute, said results provided convincing evidence that the Pfizer vaccine is “highly effective in adolescents against symptomatic Covid-19 and against all documented infections”.

Balicer, who chairs Israel’s expert advisory team on Covid-19, added: “These data make a strong argument in favour of opting in to get vaccinated, especially in countries where the virus is now widespread.”

Prof Ben Reis from Harvard University medical school in the US, who was involved in the study, said he hoped it would help to overcome vaccine hesitancy which was fuelled in part by lack of information on the jab’s effectiveness.

“This careful epidemiological study provides reliable information on vaccine effectiveness, which we hope will be helpful to those who have not yet decided about vaccination,” he said.

• Another study published on Wednesday, using data on 5.4-million people in Scotland, showed the Pfizer jab is 90% effective at preventing deaths from the Delta variant of Covid-19 among people who test positive after being double-vaccinated.

Lead author Prof Aziz Sheikh, from the University of Edinburgh’s Usher Institute, said: “If you still have not taken up your offer to be vaccinated, I would encourage you to do so based on the clear benefits it offers.”