Age-dependent immune response to the Biontech/Pfizer BNT162b2 COVID-19 vaccination
” Although the increment of antibody levels after the second immunization was higher in elderly participants, the absolute mean titer of this group remained lower than the <60 group. After the second vaccination, 31.3 % of the elderly had no detectable neutralizing antibodies in contrast to the younger group, in which only 2.2% had no detectable neutralizing antibodies.
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...”
https://pubmed.ncbi.nlm.nih.gov/33906236/
also:
“While 98.1% of the health care workers produced antibodies after vaccination, only 37.2% of the vaccinated solid organ transplant patients were positive for antibodies; 54.7% of the blood cancer patients; 82.4% of those with solid tumor cancer and 83.8% of patients with autoimmune disorders. In contrast, 94.6% of patients with HIV made antibodies.
Among patients with solid organ transplants, lung transplant patients had a particularly poor response to vaccination, with only 22.2% producing antibodies. Liver transplant patients fared best, with 60.6% of study participants producing antibodies after vaccination. Patients who received their transplant less than a year ago were less likely to respond to vaccination than those transplanted earlier.
In addition, cancer patients receiving radiation therapy and patients taking certain medications—such as antimetabolites for transplant and anti-CD20 monoclonal antibodies for autoimmune disorders—were more likely not to produce antibodies after COVID-19 vaccination. ...
https://www.upmc.com/media/news/063021-haidar-covics-interim-medrxiv