96% Britons develop antibodies after the first Covid-19 dose, shows study

New research shows that over 90 per cent of Britons develop antibodies against the novel coronavirus after getting one dose of the AstraZeneca or Pfizer vaccine, and nearly 100 per cent do so after getting the second jab.

A report published in The Guardian stated that research found that 96.42 per cent of people who had either vaccine developed antibodies 28 to 34 days after their first dose. This rose to 99.08 per cent within 7-14 days of the second jab.

Researchers from University College London (UCL) found that both vaccines were equally good at triggering antibodies needed to fight off Covid-19.

Dr Maddie Shrotri, the lead author of the paper containing the findings, said, “This is one of the earliest real-world vaccine studies in the UK and it is fantastic news.”

Over nine out of 10 adults in the UK who had either the Pfizer or AstraZeneca vaccine produced antibodies against coronavirus within a month of their first shot.

The conclusions are based on analysis of 13,232 antibody samples given by 8,517 adult participants from England and Wales in the trial, none of whom had antibodies before they had their first dose of vaccine. Anyone with antibodies was excluded. The average age of the participants was 65, reflecting the older age groups who were the first in the UK to receive Covid vaccines under the NHS’s widely-praised programme that began on December 8 last year.

According to The Guardian, the study also found that antibody rates initially rise more quickly among those who have had the Pfizer/BioNTech vaccine than those with the Oxford AstraZeneca one. However, almost identical antibody positivity rates were found among recipients of either vaccines after four weeks.

The UCL Virus Watch project team found that the vaccines stimulated the production of fewer antibodies in older people than younger ones. But after getting the second dose, people of all ages enjoyed uniformly very high antibody levels. Antibody levels after one jab were also found to be lower among people with underlying health conditions such as cancer, diabetes and heart diseases. The difference, however disappeared once all participants got their second jab, the researchers said.

Prof Rob Aldridge, the chief investigator of the UCL Virus Watch study, is quoted by The Guardian as saying: “The UCL Virus Watch data shows that for older adults and for people with underlying health conditions, the antibody response is a bit weaker after the first dose of the vaccine, but strong after the second dose.”

“It is a timely reminder about the importance of getting the second dose of the vaccine. But it is also reassuring – vaccines are our way out of the pandemic.”

The co-authors of the paper, which is undergoing peer review before publication in a medical journal, say their findings show that everyone should have both doses of their vaccine so they can be considered “safe”, especially older adults and people with existing ailments.

Over 20 million Britons have now got two doses of either one of these vaccines, or the Moderna vaccine, which was started being used in early April.

The researchers include Prof Andrew Hayward, a member of the government’s New and Emerging Respiratory Virus Threats Advisory Group (Nervtag), which has advised ministers during the pandemic. The study was funded by the NHS’s research arm, the National Institute for Health Research (NIHR), and the government’s UK Research and Innovation agency.