MADRID, 22 Abr. (EUROPA PRESS) –
New research, to be presented at this year’s European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) in Lisbon, has shown that a longer interval between primary doses of the COVID-19 vaccine can increase antibody production by up to nine times.
Understanding the immune response to COVID-19 vaccination is critical to controlling the virus and reducing the number of deaths. To find out the factors that affect the antibody response after Pfizer/BioNTech’s Covid vaccination, Dr Ashley Otter and colleagues at the UK Health Security Agency (UKHSA) measured antibody levels in blood samples. taken from nearly 6,000 healthcare workers across the UK enrolled in the SIREN (SARS-CoV-2 Infection and Reinfection and Evaluation) study.
A total of 3,989 of the 5,871 participants received their first dose of the vaccine at least 21 days earlier. 1,882 had their second dose at least 14 days earlier. Participants were classified according to their history of infection as having previously had Covid (confirmed by a PCR test or assumed due to their antibody profile) or naïve, with no history of infection. Almost all (more than 99%) of those who had not had Covid seroconverted after vaccination, which means that they created antibodies against the virus.
After dose 1, those with a prior infection had antibody levels up to ten times higher than naïve individuals, while after dose 2, those with a prior infection had antibody levels more than twice those with naïve subjects. they had not had a previous infection.
Analyzing dosing intervals, a longer dosing interval was found to be associated with up to nine-fold higher antibody levels in participants naïve over 10 weeks 11,479.73 with a more pronounced effect seen in younger participants.
Dosage interval did not affect antibody levels in those with prior infection. However, a longer interval between infection and vaccination was associated with higher antibody levels.
Those who received the first dose of the vaccine eight months after an infection had antibody levels seven times higher than those who were vaccinated three months after infection, with a plateau after eight months, suggesting that eight months after of primary infection may be an optimal time to receive the first vaccine in those with previous infection.
However, the analysis shows that, regardless of the time between infection and vaccination, all individuals have a very high antibody response after dose 2.
In addition, women and persons from an ethnic minority were associated with significantly higher antibody titers, while immunosuppression was associated with significantly lower post-vaccination antibody responses.
Dr. Otter highlights that “this study shows that a longer time between vaccine dose 1 and dose 2 results in higher antibody responses in naïve participants, strongly supporting the decision of the JCVI and the government of the UK to lengthen the interval between doses of the vaccine”.
“We have also shown that in people with prior infection, the time between exposure and vaccination plays a critical role in post-vaccination antibody responses,” he added. “However, further research is needed to determine whether these Higher antibody levels provide greater protection against COVID-19 disease and how this longer dosing interval may affect booster responses.”
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