A recent study shows that among nursing home residents, second mRNA COVID-19 booster doses provide additional protection over first booster doses against severe COVID-19 outcomes. This finding is significant as nursing homes have been disproportionately impacted by coronavirus disease since the pandemic started.
Researchers evaluated routinely obtained care data from 196 community-based nursing homes to estimate vaccination effectiveness (VE) of a second COVID-19 mRNA booster dose among NHRs previously administered three COVID-19 vaccine doses. The study period spanned the SARS-CoV-2 Omicron variant’s BA.2 subvariant (March to June 2022), BA.2.12.1 subvariant (between March and June), and Omicron BA.4/5 subvariants’ (July 2022) predominance.
Background
Nursing homes should continue to educate staff and residents on the benefits of receiving all recommended doses of the COVID-19 vaccine and offering a second booster to eligible residents. That’s according to Jodi Eyigor, director of quality and policy at LeadingAge.
In the spring of 2022, the United States Centers for Disease Control and Prevention recommended that all adults aged 50 years and older who have completed their primary series receive a second COVID-19 booster dose. However, more is needed to know about the effectiveness of this double dose in nursing home residents.
The new recommendation remains the exact compliance requirements. Still, it’s important to remember that nursing homes must provide vaccination and education for residents and staff.
Methods
Effectiveness of 2nd COVID-19 Booster in Nursing Home Residents
We conducted a target trial to evaluate the effectiveness of the 2nd COVID-19 Booster among nursing home residents. We replicated this target trial method in two disparate nursing home systems, Genesis HealthCare and Veterans Health Administration community living centers (VHA CLCs).
A subset of 1,343 residents was matched to controls precisely by the facility of residence, and index date with 1:1 nearest neighbor matching and a maximum of 0.2 standard mean difference in propensity score between pairs. In both systems, boosted residents had a significantly lower infection rate than unboosted controls.
Boosted residents were also less likely to have been hospitalized or died of SARS-CoV-2 than unboosted residents. This study showed that increasing the 2-dose staff vaccination effectively reduced SARS-CoV-2 infections among nursing home residents and SARS-CoV-2-associated hospitalization or death in staff.
Results
After completing the primary COVID-19 vaccine series and a first booster dose, a second COVID-19 bivalent booster significantly boosts immune protection against Omicron-related disease among nursing home residents and HCWs. The study, conducted in 19 states, evaluated Vaccine Effectiveness (VE) by assessing anti-Omicron S and WT RBD antibodies among nursing home residents and HCWs who had received two COVID-19 monovalent vaccines followed by a second booster dose.
Results from the study, published in MMWR on September 18, 2022, indicate that nursing home residents and HCWs who received the second COVID-19 booster shot had much lower levels of anti-Omicron S and anti-WT RBD antibodies than did those who received only one dose of COVID-19 monovalent vaccines. The VE reduction among nursing home residents was significant, from geometric mean titers of 2801.0 AU/ml in the control group to 238.0 AU/ml in the treatment group.
The VE reduction among nursing home residents is a significant step forward in the efforts to protect nursing home residents against Omicron-related disease and to prevent severe outcomes from the pandemic. Efforts to promote the take-up of the second COVID-19 booster in nursing homes will be essential to avoid hospitalization and reduce the risk of severe infection and death from this coronavirus variant.
Conclusions
As new variants emerge and make their way into nursing facilities, maximizing vaccination and booster rates among facility staff will help protect against illness and death of residents and staff and also help maintain sufficient staffing levels.
As of March 2022, about one-third of all nursing facilities nationally reported staff booster rates of over 50%, another third reported rates between 25-50%, and the remaining third reported rates under 25% (Figure 5). State variation is high, with 99% of facilities in Massachusetts reporting staff booster rates of over 50% and five % of facilities in Tennessee reporting these low rates.
In a large cohort of eligible nursing home residents, receipt of a second mRNA COVID-19 vaccine booster dose during circulation of Omicron subvariants BA.2 and BA.2.12.1 (March-June 2022), and BA.4 and BA.5 (July 2022) was 74% effective at 60 days against severe COVID-19 outcomes (including hospitalization or death) and 90% effective against death alone compared with receipt of a single booster dose. This is the first study to show that a second mRNA COVID-19 booster dose is effective during emerging Omicron subvariants and should be part of a public health strategy to prevent severe disease in nursing home residents.
