A study by Public Health England (PHE) found that the Pfizer vaccine for coronavirus is 88% effective against the Indian variant after two doses.
Both Pfizer and AstraZeneca were found to be nearly as effective against the disease symptoms of the B1617.2 strain as they are against the UK variant after the second dose.
However, it was only 33% effective three weeks after the first dose.
Ireland’s chief medical officer, Dr Tony Holuhan, previously described the Indian alternative as «a dark cloud on the horizon».
The study, conducted between April 5 and May 16, found that the Pfizer vaccine was 88% effective against symptomatic diseases than the Indian variant two weeks after the second dose, compared to 93% effective against the UK strain.
Meanwhile, AstraZeneca’s hit was 60% effective, compared to 66% against the British variant during the same period.
Both vaccines were 33% effective against symptomatic diseases of the Indian type three weeks after the first dose, compared to approximately 50% against the UK strain.
About 12,675 genome-sequenced cases were included in the analysis, but only 1,054 cases were of the Indian species.
The study included data for all age groups from April 5 to cover the period since the breed’s emergence.
New data from PHE shows that there were at least 2,889 cases of the Indian variant recorded in England from February 1 this year to May 18.
In Ireland, 72 cases of this troubling type have been identified – B1617.2 – up from 59 cases earlier this week and 41 last week.
There is greater confidence in the data from the first vaccine dose than from the second vaccine dose, said Dr. Jimmy Lopez Bernal, consultant medical epidemiologist at PHE and lead author of the study.
He told reporters on Saturday, «There are more numbers who were vaccinated with a single dose. So I think we classify that as moderate certainty about the first dose, but low levels of confidence about the second dose.»
However, Professor Susan Hopkins, Director of Covid-19 Strategic Response at PHE, said the data trend was «crystal clear» and was heading in the «right direction».
PHE said the difference in efficacy between vaccines may be due to the second AstraZeneca dose released at a later date than the Pfizer vaccine.
The data also shows that the AstraZeneca Strike takes longer to reach maximum effectiveness.
PHE added that there are not enough cases and follow-up periods to estimate the efficacy of the vaccine against severe results from the Indian variant but that this will be evaluated over the coming weeks.
Dr Mary Ramsay, Head of Immunization at PHE, added: “This study provides reassurance that two doses of any vaccine provide high levels of protection against symptoms of the B1617.2 variant.
«We expect vaccines to be most effective in preventing hospitalization and death, so it is imperative to obtain both doses to obtain maximum protection against all current and emerging variants.»
In response to the results, Professor Adam Fenn, Professor of Pediatrics at the University of Bristol, said: “Overall the results are encouraging in that vaccines continue to provide beneficial protection.
«However, protection after the first dose appears to have diminished to a degree of potential significance.»
Last night, the National Public Health Emergencies Team (Nphet) reported 381 new cases of Covid-19 in Ireland.
It came as six countries – Andorra, Georgia, Kuwait, Mongolia, Nigeria and Puerto Rico – were removed from the hotel’s mandatory quarantine list.