COVID-19 Vaccine Booster Dose Reduces Infection, Hospitalization, Death from Virus in Long-Term Care Facilities

A third dose of the BNT162b2 (Pfizer-BioNTech) mRNA COVID-19 vaccine was associated with a reduced burden of SARS-CoV-2 infection, COVID-19–related hospitalizations, and COVID-19–related deaths in long-term care (LTC) facilities, according to study published in JAMA Network Open.

During the surge caused by the Delta variant in mid-April 2020, Israel established a national level task force with the aim of protecting residents of LTC facilities from the spread of SARS-CoV-2, considering the high-risk population, overcrowding, and lack of training for health care workers in these facilities.

The program, enforced by the task force in all LTC facilities in Israel, included routine weekly SARS-CoV-2 RT-PCR screening tests on all LTC facility personnel. Additionally, the task force was responsible for vaccinating all health care workers and residents of LTC facilities, including vaccination with a third BNT162b2 dose in August 2021.

As part of the task force routine surveillance, researchers conducted an observational cohort study to examine the association of BNT162b2 third dose (first booster dose) with overall SARS-CoV-2 infection, COVID-19 hospitalizations, and mortality among residents of LTC facilities.

They conducted nationwide COVID-19 surveillance in LTC facilities in Israel between August and October 2021. Participants included residents of LTC facilities 60 years of age and older. They measured cumulative incidences of SARS-CoV-2 infection, COVID-19 hospitalizations, and COVID-19-related deaths more than 7 days after vaccination with the third dose.

A total of 18,611 residents were included in the analysis. Of these, 12,715 (68.3%) were female, 463 (2.5%) were from the Arab population, 16,976 (91.2%) were from the general Jewish population, and 618 (3.3%) were from the ultraorthodox Jewish population. The mean (SD) age of participants was 81.1 (9.2) years.

There were 16,082 residents who received their first booster dose (third dose), and 2529 residents were vaccinated with 2 doses at least 5 months earlier. The median (IQR) follow-up durations were 66 (60-70) days among 3-dose recipients and 56 (53-62) days among 2-dose recipients.

Researchers found that 107 residents had SARS-CoV-2 infection after 7 days following vaccination with the booster dose compared with 185 among the 2-dose group (cumulative incidence: 0.7% vs 7.5%; adjusted hazard ratios [HR], 0.11 [95% CI, 0.07-0.15]).

The respective adjusted HRs were found to be 0.07 (95% CI, 0.03-0.14) and 0.10 (95% CI, 0.04-0.24) for the associations of vaccination with the third dose with hospitalization for mild-to-moderate COVID-19 and severe illness.

Only 5 COVID-19-related deaths occurred among the third dose group during the follow-up period compared with 22 deaths among the 2-dose group (cumulative rate: 0.04% vs 0.9%; adjusted HR, 0.04 [95% CI, 0.009-0.16]).

These findings indicate significant inverse associations between vaccination with the third dose of the BNT162b2 vaccine with overall SARS-CoV-2 infection, COVID-19 hospitalizations, severe disease, and COVID-19–related deaths among LTC facility residents. These results were measurable following 7 days from vaccination, demonstrating a rapid reduction in an individual’s risk of infection and disease.

The authors highlighted the role of the BNT162b2 third dose vaccination in controlling the Delta surge by preventing SARS-CoV-2 infection and COVID-19 hospitalizations and deaths among the older vulnerable population, particularly in LTC facilities.

“Our study demonstrated that in the context of the frail population of LTCF residents, during the Delta variant surge, the third dose administration was essential to efficiently lower the risk of overall infection and not only severe disease, thus reducing the potential of the virus transmission in these facilities,” the authors concluded.

The study has some limitations, including the observational design. Researchers did not have information on the reasons for the option not to receive the third dose of the vaccine.

Additionally, information on comorbidities was lacking. Therefore, researchers could not assess whether the association between vaccination with the third dose and the study endpoints may differ among residents with certain comorbidities.

However, the authors note strengths of the study, including the systematic testing performed within the framework of the task force surveillance and the equal offering of vaccination to all LTC facilities across the country with high uptake.

Reference

Muhsen K, Maimon N, Mizrahi A Y, et al. Association of BNT162b2 vaccine third dose receipt with incidence of SARS-CoV-2 infection, COVID-19–related hospitalization, and death among residents of Long-term care facilities, August to October 2021. JAMA Netw Open. 2022;5(7):e2219940. doi:10.1001/jamanetworkopen.2022.19940