Two doses of Covid vaccines present safety towards India variant
A healthcare worker holds syringes with the Moderna and Pfizer vaccines against the coronavirus disease (COVID-19) at a vaccination centre, in El Paso, Texas, May 6, 2021.
Jose Luis Gonzalez | Reuters
A new study has found that two doses of either the Pfizer-BioNTech or AstraZeneca-University of Oxford vaccine give effective protection against the Covid variant first discovered in India, however it underscored the need for two doses, as both vaccines were significantly less effective after only one shot.
The study, led by Public Health England also found that two doses of the vaccine were similarly as effective at protecting against the variant that first emerged in the U.K. and has since become a dominant strain in the West.
Dr Jenny Harries, CEO of the U.K. Health Security Agency, told the BBC that the study provided the “first real-world evidence of vaccine effectiveness” against the variant first identified in India.
Conducted between April and May, the research found that the Pfizer-BioNTech vaccine was 88% effective against symptomatic disease from the B.1.617.2 Covid variant — a sub-type of a variant that emerged in India last fall which has since spread to Europe — two weeks after the second dose. The vaccine was 93% effective two weeks after the second dose against the B.1.1.7 variant which was first discovered in the U.K. last fall.
Meanwhile, two doses of the AstraZeneca vaccine were found to be 60% effective against symptomatic disease from the B.1.617.2 variant from India, compared to 66% effective against the variant from the U.K.
“Vaccine effectiveness against symptomatic disease from the B.1.617.2 variant is similar after 2 doses compared to the B.1.1.7 (Kent) variant dominant in the U.K., and we expect to see even higher levels of effectiveness against hospitalisation and death,” the study authors wrote. The results were published Saturday as a pre-print and the study has not yet been peer reviewed.
PHE said the difference in effectiveness between the vaccines after two doses “may be explained by the fact that rollout of second doses of AstraZeneca was later than for the Pfizer-BioNTech vaccine, and other data on antibody profiles show it takes longer to reach maximum effectiveness with the AstraZeneca vaccine.”
However, both vaccines were only 33% effective against symptomatic disease from B.1.617.2 three weeks after the first dose. In the same time frame, they were found to be 50% effective against the B.1.1.7 variant.
Variant of concern
The variant first discovered in India has been blamed for causing a dramatic third wave of infections in the country, overwhelming hospitals and causing thousands of deaths this spring. There were concerns that Covid vaccines could be rendered less effective by the variant so the latest data should help allay those concerns.
The India variant has been detected in numerous other countries now, according to the World Health Organization, which dubbed it a “variant of concern” in early May.
The PHE study analyzed data from 1,054 people, of all age groups and several ethnicities, confirmed as having the B.1.617.2 variant through genomic sequencing. The data was collected from April 5 and hence covers the period since the B.1.617.2 variant (one of three variant sub-types found in India) emerged in parts of the U.K.
“As with other variants, even higher levels of effectiveness are expected against hospitalisation and death. There are currently insufficient cases and follow-up periods to estimate vaccine effectiveness against severe outcomes from the B.1.617.2 variant. PHE will continue to evaluate this over the coming weeks,” the study’s authors added.
Responding to the study, the U.K.’s Health Secretary Matt Hancock described the findings as “groundbreaking – and proves just how valuable our Covid-19 vaccination programme is in protecting the people we love.”
The U.K. has given over 22 million people two doses of a Covid vaccine, while 72% of the population (or almost 40 million people) have had one shot, government data shows.
Hancock said the latest data emphasized “how important the second dose is to secure the strongest possible protection” against Covid-19 and its variants.
Separate PHE analysis indicated that the country’s Covid-19 vaccination program has so far prevented 13,000 deaths and around 39,100 hospitalizations in older people in England, up to May 9.
Comments are closed.