High levels of antibodies have been found in people of all ages who have received two doses of the Pfizer / BioNTech COVID-19 vaccine, a study prospect has suggested.
Researchers also found high responses about a single dose of the vaccine among those previously infected with the SARS-CoV-2 virus.
However, the data from round 5 of the REACT-2 study, conducted by Imperial College London (ICL), were insufficient to reveal the effect of antibody detection on hospitals and deaths.
The study also suggested that confidence in the vaccine was high, but lower in some groups, including key workers and those from ethnic minorities.
Lateral Antibody Flow Tests
The findings were based on a self-experiment of more than 155,000 participants in England using late-prick finger-streaming devices between 26 January and 8 February.
For the first time, ICL researchers were able to capture the first effects of the COVID-19 vaccine program.
There were sufficient data to record the effects of the Pfizer / BioNTech vaccine, but it was not the effects of the AstraZeneca / Oxford vaccine that started its later release.
Of the participants, 18,000 had received at least one dose of the vaccine.
Overall, antibody frequency was 13.9% of those tested. That ranged from 9.8% for the non-vaccinated group to 37.9% for participants who had been vaccinated.
Of those who received two doses of the vaccine, antibody sensitivity was 88% in those over 80, rising to 95.5% in those under 60.
After a single dose of the Pfizer / BioNTech vaccine, 84.1% of people under 60 tested positive for antibodies after 21 days. That figure peaked in those under 30 at 94.7%, declining with age to 73.7% at 60, and 34.7% in those over 80.
Helen Ward, professor of Public Health at ICL, said: “Our findings suggest that it is very important for people to take a second dose when offered.”
Although antibody sensitivity declined with increasing age, a 90.1% response was observed in COVID-19-tested or previously suspected vaccine recipients.
“We can say from our data that we are seeing very favorable antibody results in people who have previously received COVID after one dose to some extent that they are at least as good as people who have received two doses of Pfizer / BioNTech vaccine, “said Graham Cooke, professor of infectious diseases at ICL.
Professor Cooke told a briefing given by the Science Media Center that “previously infected people do not appear to have such high levels of their own illness, showing” value in receiving that first dose in a previous infectious condition ”.
Antibody frequency in unvaccinated people was found to vary across the country. The highest rate (16.9%) was seen in London.
Black people were also more likely to test positive at 22.4%, followed by Asian people at 20%, compared to 8.5% of White people.
Antibody frequency also varied by employment, with the highest levels found in health care workers (21.9%) and social care workers (24.2%).
People in public office such as police officers and teachers were also more likely to be tested than non-key workers.
Vaccine confidence
Research conducted in conjunction with Ipsos MORI voters found high levels of confidence in the vaccine, with 92% of people saying they had accepted or intended to accept the vaccine offered.
However, this varied by age and race.
The lowest levels of confidence were observed in young people and those of black ethnicity.
Particular concerns were seen about pregnancy, fertility and allergies.
“We know that some organizations have concerns about the vaccine, including some people at increased risk from COVID-19, so it’s very important that they have opportunities to consider them and find out more. out, “said Dr. Ward.
Expert opinion examined
Commenting on the study, Dr Simon Clarke, associate professor of cell microbiology at Reading University, said: “It is worrying in studies of people aged 70 and over that one dose of the vaccine was associated with significantly lower levels of antibodies than in younger age groups, or in those who received COVID-19 prior to vaccination.
“This shows that, with this vaccine, the immune response is much greater in individuals who have been shown twice, either through pre-infection or through dual vaccination.”
Kevin McConway, professor emeritus in applied statistics at the Open University, said: “This study did not measure whether people were sick, just responded to antibody, so it cannot tell us directly about the effect of vaccination on eradicating COVID ‘s disease. But the signs are good for people who have received two doses of this vaccine. “
Marian Knight, professor of maternal and child population health at Oxford University, said: “The large size of the study provides additional reassurance that confidence in the vaccine is high in most population groups. However, it is worrying that participants report concerns about pregnancy and planned or routine fertility.
“Guidance from the Royal College of Lawyers and Gynecologists is clear that women trying to conceive a child do not need to avoid vaccination after vaccination and women should be assured that there is no evidence that recommends that COVID-19 vaccines affect fertility. “
REACT-2 Round 5: increasing SARS-CoV-2 antibodies show second-wave effect and vaccine distribution in England, Helen Ward et al. Preprint.