Luke O’Neill: Healthy under-60s do not need booster but that could change in six months

Pfizer/BioNTech vaccine effectiveness ‘falls to 47% six months after second dose’, according to Lancet study

Immunologist Prof Luke O’Neill has said that at present healthy people under the age of 60 do not need a booster vaccine, but that the situation could change.

He was responding to a report in the Lancet medical journal that said the efficacy of the Pfizer/BioNTech coronavirus vaccine dropped to 47 per cent from 88 per cent six months after the second dose, according to data published on Monday.

Prof O’Neill said the data suggested the drop was due to waning efficacy rather than more contagious variants.

There was still protection against hospitalisation, added Prof O’Neill on RTÉ radio’s Today with Claire Byrne.


“The vaccine is holding firmly against Delta is the message.”

“If you’re healthy and under 60 you don’t need a booster,” he said. “But that may change when it gets to nine months out or 12 months, then that might be slightly different, that’s why the EMA [European Medicines Agency] have said just in case, anybody over 18 might be given a booster – each government is given the job itself to decide what to do with the EMA guideline.”

However, if there was evidence of increased risk in six months time “then you may start giving a booster – it may well become a three shot vaccine, finally. The Hep C vaccine is three shots, some vaccines are three shots, it may turn out that we need three shots to be fully protected.”

There was some evidence that the Delta variant of the virus “may be as bad as it’s going to get. There’s some hope Delta may be the last throw of the dice for the virus”.

The research, published in the Lancet medical journal, had been previously released in August ahead of peer review. The analysis showed the vaccine’s effectiveness in preventing hospitalisation and death remained high at 90 per cent for at least six months, even against the highly contagious Delta variant.

Scientists from Pfizer and US healthcare provider Kaiser Permanente studied electronic health records of roughly 3.4 million people who were members of Kaiser Permanente Southern California between December 2020 – when the vaccine first became available – and August 2021.

"Our variant-specific analysis clearly shows that the [Pfizer/BioNTech] vaccine is effective against all current variants of concern, including Delta," said Luis Jodar, senior vice president and chief medical officer at Pfizer vaccines.

A potential limitation of the study, however, was a lack of data on adherence to masking guidelines and occupations in the study population, which could have affected frequency of testing and likelihood of exposure to the virus.

Vaccine effectiveness against the Delta variant was 93 per cent after the first month, declining to 53 per cent after four months, according to the research. Against other coronavirus variants, efficacy declined to 67 per cent from 97 per cent.

"To us, that suggests Delta is not an escape variant that is completely evading vaccine protection," said study leader Sara Tartof of Kaiser Permanente Southern California.

“If it was, we would probably not have seen high protection after vaccination, because vaccination would not be working in that case. It would start low, and stay low.”

Testing for variants is more likely to fail in vaccinated individuals, which could lead to overestimation of variant-specific effectiveness in the study, the authors warned

The US Food and Drug Administration has authorised the use of a booster dose of the Pfizer/BioNTech vaccine for older adults and some Americans at high-risk of getting infected.

Scientists have called for more data on whether boosters should be recommended for all. – Addtional reporting: Reuters