According to research published in The Lancet journal, total antibody levels begin to decline six weeks after vaccination with AstraZeneca and Pfizer vaccines. They can also decrease by more than 50% over a period of 10 weeks.
Researchers from University College London (UCL), in the UK, noted that if antibody levels continue to drop at this rate, there is concern that the protective effects that vaccines have against new variants of cancer may also start to wear off.
They said that it was impossible to predict when this might happen.
UCL Virus Watch also showed that antibody levels were significantly higher after two doses Pfizer vaccine than they were after two doses AstraZeneca preventive (known as Covishield India).
The levels of antibodies in people who were vaccinated were higher than those with a prior SARS-CoV-2 virus infection.
Researchers found that the findings, which were based on data from more than 600 people aged 18 or older, were consistent across all age groups, regardless of chronic illness, gender, and sex.
Although the clinical implications of declining antibody levels are still unclear, they were expected to decline. Current research also shows that vaccines continue to be effective against severe diseases.
Pfizer’s antibody levels decreased from a median of 7506 Units/mL (U/mL), at 21-41 days to 3320 Units/mL (U/mL), at 70 days or more.
AstraZeneca vaccine antibody levels were reduced by a median of 1201 U/mL from 0-20 days to just 190 U/mL after 70 days or more, a five-fold decrease.
Professor Rob Aldridge, UCL Institute of Health Informatics, stated that when we think about who should get booster doses, our data suggest that people who were vaccinated the earliest, especially with AstraZeneca, have the highest antibody levels.
According to the researchers, these findings support the recommendation that patients who are clinically vulnerable and those over 70 years old should be given booster doses.
Gracia is graduated from a reputed university in London. She is a senior content writer at TechieGuard, where she covers media and advertising and co-hosts the Original Content podcast.