Antibody responses to vaccination against SARS-CoV-2, the coronavirus that causes COVID-19, wane quickly in patients receiving dialysis, and this decline may increase the risk for breakthrough infection, new data suggest.
The findings are from a prospective case-control study of a nationwide sample of 4791 patients in which investigators examined the relationship between levels of vaccine-induced antibodies to the receptor-binding domain (RBD) of SARS-CoV-2 and development of breakthrough infection. They matched each breakthrough case to 5 patients (control) by age, sex, and vaccination month and adjusted for diabetes status and region of residence.
Among the 2563 fully vaccinated patients, the estimated proportion with an undetectable antibody response increased from 6.6% at 14-30 days after vaccination to 20.2% at 5-6 months after vaccination, Shuchi Anand, MD, of Stanford University in Palo Alto, California, and colleagues reported in Annals of Internal Medicine. Estimated median index values decreased from 91.9 at 14 to 30 days after vaccination to 8.4 at 5 to 6 months after vaccination.
During a median follow-up period of 152 days, clinically documented COVID-19 developed in 56 (2%) of the fully vaccinated patients.
Compared with pre-breakthrough index RBD antibody values of 23 or higher (equivalent to 506 binding antibody units [BAU]/ mL or greater), pre-breakthrough RBD values less than 10 (equivalent to 218 BAU/mL) and values from 10 to less than 23 were significantly associated with an 11.6- and 6.0-fold greater likelihood of breakthrough infection, respectively, Dr Anand and colleagues reported.
“Our analysis suggests that a majority of vaccinated patients have circulating antibody levels 5 months after vaccination that render them vulnerable to a breakthrough infection,” the authors wrote. “Although the overall number of breakthrough infections was low, even in the group with low antibody levels, exposure to SARS-CoV-2 is not uniform and patients are likely to have used other mitigation strategies, such as masking and social distancing.”
The investigators acknowledged that reliance on a single measure of vaccine response and ascertainment of COVID-19 diagnoses from electronic medical records were study limitations.
Disclosure: This research was supported by Ascend Clinical Laboratory. Please see the original reference for a full list of disclosures.
Anand S, Montez-Rath ME, Han J, et al. SARS-CoV-2 vaccine antibody response and breakthrough infection in patients receiving dialysis. Ann Intern Med. Published online December 14, 2021. doi:10.7326/M21-4176