The rapid dissemination of the SARS-CoV-2 new variants of concern and the waning in vaccine-acquired immunity, lead to the introduction of booster shots. In July 2021, Israel was the first country to introduce a third vaccine dose 5 months or more following the second vaccine dose, which was associated with high protection against overall SARS-CoV-2 infeccion, hospitalizations, and deaths in the general population.
In November 2021, Israel first identified the Omicron variant, which became the dominant variant worldwide in January 2022. Even people with full vaccination were getting infected in December 2021 with a marked rise in infections. That is why the Israel Ministry of Health approved a 4th BNT162b2 dose (BioNTech, Pfizer vaccine) in December 2021.
Recently, a group of researchers seeked to determine the association of the 4th dose of vaccine against SARS-CoV-2-related infections, hospitalizations, and deaths in long-term care facility residents. Their results appear in the journal JAMA Internal Medicine.
High Protection Against Hospitalizations and Deaths
For the study, the team included a total of 43,775 residents of long-term care facilities in Israel between January 10 and March 31 2022. All residentes were 60 years or older, with a mena age of 80.1 years.
24 088 (55.0%) and 19 687 (45.0%) received the fourth and third dose (4 months previously or earlier), respectively.
The incidence of overall SARS-CoV-2 infection was lower among the 4-dose vs 3-dose recipients.SARS-CoV-2 infection was detected among 4058 residents who received the fourth dose of the vaccine vs 4370 among residents who received 3 doses, yielding cumulative incidences of 17.6% vs 24.9%.
There were 217 hospitalizations for COVID-19 of mild-to-moderate severity among the 4-dose recipients compared with 493 among the 3-dose recipients. For severe hospitalizations the 4-dose group had 108 compared with 259 in the 3-dose group. Lasty, there were 39 deaths among the 4-dose group and 85 in the 3-dose group.
The researchers concluded that a 4th dose of the BioNTech, Pfizer vaccine was associated with high protection against COVID-19 hospitalizations and deaths among residents of long-term care facilities, with the 4th dose being associated with a 34% protection against infection, 64-67% against hospitalizations, and 72% against deaths.
The authors of the study recommended that elderly patients should get their booster due to the increased benefits that it provides.
Khitam Muhsen, et al. Association of Receipt of the Fourth BNT162b2 Dose With Omicron Infection and COVID-19 Hospitalizations Among Residents of Long-term Care Facilities. 2022. JAMA Intern Med. doi:10.1001/jamainternmed.2022.2658