Pfizer vaccine produces less antibodies against Delta variant: Study

New data shows Delta variant could also lead to increased risk of hospitalization compared to Alpha variant.

Pfizer vaccine produces less antibodies against Delta variant: Study

New data by British scientific researchers shows that those who have received the Pfizer vaccine have fewer antibodies against the Delta variant which originated in India compared to other variants, local media reported.

Public Health England (PHE) announced that the Delta variant is the dominant variant in the UK and that it could also lead to increased risk of hospitalization compared to the UK variant.

The research on the Pfizer vaccine was carried out by the Francis Crick Institute and the National Institute for Health Research (NIHR) UCLH Biomedical Research Centre, both in London.

Researchers analyzed 250 blood samples and found that the level of antibodies also decreased as age increased and time progressed.

They found that people who received only one dose of Pfizer produced less antibodies against the Delta variant, than the UK variant, now known as Alpha.

The UK government has previously suggested vaccine boosters this autumn.

UCLH infectious diseases consultant Emma Wall 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.”

Commenting on the data, Eleanor Riley, professor of immunology and infectious disease at the University of Edinburgh, said: “These data cannot tell us whether the vaccine will be any less effective at preventing severe disease, hospitalization and death; we need to wait for the actual data on these outcomes.”

“There are reasons to be optimistic on this score, as other immune responses -- such as T cells -- also contribute to protection against severe disease and these may be less affected by the mutations that affect antibody neutralization.”

Dominant Delta variant

New government data also showed that the Delta variant now accounts for 75% of new COVID-19 cases in the UK.

PHE announced in a new report that hospitalizations from the variant have approximately doubled in a week. PHE analysis of the data showed that the Indian variant had a 2.61 times higher risk of hospitalization within 14 days.

Professor Adam Finn of the University of Bristol and a member of the Joint Committee on Vaccination and Immunisation was quoted by the Guardian as saying: “Although only a small number of cases end up in hospital, the proportion is about twice as high for Delta cases than Alpha cases in both England and Scotland.”

“The number of cases is still small, but if this trend continues and case numbers continue to rise quickly, that would point to a larger number of people being seriously affected as this variant continues to replace the alpha variant over coming weeks.”

Professor Christina Pagel, director of UCL’s Clinical Operational Research Unit, said: “Every technical report seems to bring worse news. Added to increased transmissibility and some vaccine escape, we now have evidence that your chance of being hospitalised might be twice as high with the Delta variant than with the Alpha variant.”

“This makes it harder for vaccines to weaken the link between cases and hospitalisations,” she said.

The Delta variant is mainly concentrated in a few hotspots in England. The hottest of these is in northwest England, in Bolton and Blackburn with Darwen. Other hotspots include Bedford in central England.