Long-term follow-up of patients after COVID-19: adherence to SARS-CoV-2 vaccination and immune status

ABSTRACT

Objective. To assess the adherence of COVID-19 convalescents to vaccination against SARS-CoV-2 and immune status based on long-term follow-up (12 months or more after hospital discharge). Material and methods. Using the TARGET-VIP registry, 775 patients (age 57.5+/-1.4 years;50.6% males) with the in-hospital diagnosis of COVID-19 were followed for 13.7+/-3.0 months after discharge. Comparison groups included 190 (24.5%) subjects vaccinated against SARS-CoV-2 and 585 (75.5%) unvaccinated during the follow-up period. Immune status was assessed in a representative sample of 283 (36.5%) patients (age 56.9+/-12.7 years, 44.9% males) who came for outpatient visits 14.6+/-4.1 months after hospital discharge, including 97 (34.3%) vaccinated and 186 (65.7%) unvaccinated against SARS-CoV-2. Results. No significant differences were found between the SARS-CoV-2 vaccinated and unvaccinated groups in age, gender char-acteristics, cardiovascular disease rate, chronic non-cardiac disease rate, and proportion of smokers. In the unvaccinated group, a higher proportion of patients with a history of ICU treatment for COVID-19 and/or grade 3-4 lung injury measured by CT scans was observed 55.0% versus 46.8% (p=0.048). The vaccinated group included less active smokers 3.7% versus 6.0% (p=0.22). Among the patients who came to the visit, antibody titer of IgG type N was increased in 50.4% of cases, and antibody titer of IgG type S (quantitatively) - in 98.6% of cases. After 14.6+/-4.1 months of follow-up, the SARS-CoV-2 vaccinated group (12.3+/-2.7 months after COVID-19) had higher IgG type S levels (505+/-103 versus 376+/-171 BAU/mL;p<0.001) compared with unvaccinated patients and no statistically significant difference in IgG (type N) and IgM titers. The SARS-CoV-2 vaccinated group had significantly higher rates of influenza vaccination both before COVID-19 (34.8% versus 21.9%;p=0.0004) and after hospitalization for COVID-19 (37.0% versus 15.0%;p<0.0001) compared with the unvaccinated group. After COVID-19, compared to the period before hospitalization, the proportion of vaccinated against influenza in the group vaccinated against SARS-CoV-2 increased (from 34.8% to 37.0%;p=0.65) and decreased in the group unvaccinated against SARS-CoV-2 (from 21.9% to 15.0%;p=0.003). Conclusion. The study showed that only 24.5% of COVID-19 survivors were subsequently vaccinated against SARS-CoV-2 over a fol-low-up period of 13.7+/-3.0 months. One year after hospital discharge, 50.4% of patients had elevated IgG type N titer, and 98.6% of patients had high IgG type S titer, significantly higher in vaccinated patients. Adherence to influenza vaccination after hospitalization for COVID-19 increased in patients subsequently vaccinated against SARS-CoV-2 and decreased in unvaccinated patients. Copyright © 2022, Media Sphera Publishing Group. All rights reserved.