COVID-19 mRNA booster vaccination induces robust antibody responses but few adverse events among SARS-CoV-2 naïve nursing home residents

• Published in: Scientific reports Vol. 14; no. 1; pp. 23295 - 9
• Main Authors: Itamochi, Masae, Yazawa, Shunsuke, Saga, Yumiko, Shimada, Takahisa, Tamura, Kosuke, Maenishi, Emi, Isobe, Junko, Sasajima, Hitoshi, Kawashiri, Chikako, Tani, Hideki, Oishi, Kazunori
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 07.10.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 692/699/255; 692/699/255/2514; Adult; Adverse events; Aged; Aged, 80 and over; Antibodies; Antibodies, Neutralizing - blood; Antibodies, Neutralizing - immunology; Antibodies, Viral - blood; Antibodies, Viral - immunology; Antibody Formation; Antibody response; COVID-19; COVID-19 - immunology; COVID-19 - prevention & control; COVID-19 vaccines; COVID-19 Vaccines - administration & dosage; COVID-19 Vaccines - adverse effects; COVID-19 Vaccines - immunology; Female; Humanities and Social Sciences; Humans; Immunization; Immunization, Secondary; Immunoglobulin G; Immunoglobulin G - blood; Immunoglobulin G - immunology; Life-threatening adverse events; Male; Middle Aged; mRNA; MRNA booster vaccination; multidisciplinary; Nursing home residents; Nursing Homes; Older people; Omicron variants; SARS-CoV-2; Science; Science (multidisciplinary); Severe acute respiratory syndrome coronavirus 2; Vaccination; Vaccination - adverse effects; COVID-19; SARS-CoV-2; MRNA booster vaccination; Nursing home residents; Omicron variants; Life-threatening adverse events
• DOI: 10.1038/s41598-024-73004-8
• ISSN: 2045-2322

Residents in nursing homes face heightened COVID-19 risks. We aimed to assess the adverse events (AEs) rates and antibody responses after the first to the fifth dose of COVID-19 mRNA vaccination in a nursing home cohort. Ninety-five SARS-CoV-2 naïve participants consisted of 26 staff (median age, 51 years) and 69 residents (median age, 88 years). Life-threatening AEs were reported in neither residents nor staff. The severity of non-life-threatening AEs was graded, and severe AEs were reported only in staff. The AEs rates were considerably lower in residents, compared to those in staff. Anti-RBD IgG and the neutralizing titers (NTs) against Wuhan and Omicron BA.4/BA.5 did not differ significantly between those with ‘any AE’ and ‘no AE’ among both staff and residents two months after the second, third and fifth doses, while the anti-RBD IgG significantly differed between two groups after third dose in residents. These findings suggest that the anti-RBD IgG and the NTs increase regardless of the occurrence of AEs. Our study underscores a robust antibody response in both in staff and residents, and fewer AEs following COVID-19 vaccination in SARS-CoV-2 naïve residents than staff, supporting the recommendation for mRNA booster doses in older adults at high-risk care facilities.