COVID-19: People who have had Pfizer vaccine have lower antibodies targeting Indian variant, study suggests
People who have received the Pfizer/BioNTech vaccine have fewer antibodies targeting the Indian COVID-19 variant compared to other strains, new data suggests.
Levels of these antibodies are lower with increasing age and decline over time, the analysis of blood samples from 250 healthy people also suggests.
This provides even more evidence in support for vaccine boosters for the vulnerable come autumn, researchers believe.
The data, from the Francis Crick Institute and the National Institute for Health Research (NIHR) UCLH Biomedical Research Centre, also supports current plans to reduce the dose gap between the jabs.
It found that after just one dose of the Pfizer jab, recipients were less likely to develop antibody levels against the Indian variant, also known as Delta, as high as those seen against the UK variant, now known as Alpha.
But scientists say antibody levels alone do not predict vaccine effectiveness and prospective studies are also needed.
Lower levels of antibodies could still protect against the virus, according to experts.
Now believed to be the dominant COVID strain in the UK, early evidence suggests the Indian variant may lead to an increased risk of being admitted to hospital compared with the UK variant.
Public Health England data up to 2 June shows that a total of 12,431 cases of the Indian variant have been confirmed in the UK – up 79% from the previous week’s total of 6,959.
Emma Wall, UCLH Infectious Diseases consultant and senior clinical research fellow for the Legacy study, said: “This virus will likely be around for some time to come, so we need to remain agile and vigilant.
“Our study is designed to be responsive to shifts in the pandemic so that we can quickly provide evidence on changing risk and protection.
“The most important thing is to ensure that vaccine protection remains high enough to keep as many people out of hospital as possible.”
She said the best way to keep hospitalisations as low as possible is to quickly deliver second doses and provide boosters to those with weakened immune systems.
The study is the largest one published to date which investigates vaccine-induced antibody neutralising capacity against the newest COVID variants in health adults.
Researchers have submitted their findings to the Genotype-to-Phenotype National Virology Consortium (G2P-UK), the New and Emerging Respiratory Virus Threats Advisory Group (Nervtag) and the Joint Committee on Vaccination and Immunisation (JCVI).
Eleanor Riley, professor of immunology and infectious disease, University of Edinburgh, said: “These data cannot tell us whether the vaccine will be any less effective at preventing severe disease, hospitalisation and death; we need to wait for the actual data on these outcomes.”
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