A study compared the immune protection elicited by the Pfizer COVID vaccine in people under 60 and people over 80. Neutralizing antibody levels were significantly lower in elderly patients.
After the second dose, a third of the elderly group had no detectable neutralizing antibodies, whereas only two percent of the younger group had no detectable neutralizing antibodies. Read the study.
Age-dependent immune response to the Biontech/Pfizer BNT162b2 COVID-19 vaccination | Clinical Infectious Diseases | Oxford Academic
Conclusion
Our data showed differences between the antibody responses raised after the first and second BNT162b2 vaccination, in particular lower frequencies of neutralizing antibodies in the elderly group.
This suggests that this population needs to be closely monitored and may require earlier revaccination or/and an increased vaccine dose to ensure stronger long lasting immunity and protection against infection.