Abstract
BACKGROUND
On January 2, 2022, Israel began administering a fourth dose of BNT162b2 vaccine to persons 60 years of age or older. Data are needed regarding the effect of the fourth dose on rates of confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and of severe coronavirus disease 2019 (Covid-19).
METHODS
Using the Israeli Ministry of Health database, we extracted data on 1,252,331 persons who were 60 years of age or older and eligible for the fourth dose during a period in which the B.1.1.529 (omicron) variant of SARS-CoV-2 was predominant (January 10 through March 2, 2022). We estimated the rate of confirmed infection and severe Covid-19 as a function of time starting at 8 days after receipt of a fourth dose (four-dose groups) as compared with that among persons who had received only three doses (three-dose group) and among persons who had received a fourth dose 3 to 7 days earlier (internal control group). For the estimation of rates, we used quasi-Poisson regression with adjustment for age, sex, demographic group, and calendar day.
RESULTS
The number of cases of severe Covid-19 per 100,000 person-days (unadjusted rate) was 1.5 in the aggregated four-dose groups, 3.9 in the three-dose group, and 4.2 in the internal control group. In the quasi-Poisson analysis, the adjusted rate of severe Covid-19 in the fourth week after receipt of the fourth dose was lower than that in the three-dose group by a factor of 3.5 (95% confidence interval [CI], 2.7 to 4.6) and was lower than that in the internal control group by a factor of 2.3 (95% CI, 1.7 to 3.3). Protection against severe illness did not wane during the 6 weeks after receipt of the fourth dose. The number of cases of confirmed infection per 100,000 person-days (unadjusted rate) was 177 in the aggregated four-dose groups, 361 in the three-dose group, and 388 in the internal control group. In the quasi-Poisson analysis, the adjusted rate of confirmed infection in the fourth week after receipt of the fourth dose was lower than that in the three-dose group by a factor of 2.0 (95% CI, 1.9 to 2.1) and was lower than that in the internal control group by a factor of 1.8 (95% CI, 1.7 to 1.9). However, this protection waned in later weeks.
CONCLUSIONS
Rates of confirmed SARS-CoV-2 infection and severe Covid-19 were lower after a fourth dose of BNT162b2 vaccine than after only three doses. Protection against confirmed infection appeared short-lived, whereas protection against severe illness did not wane during the study period.
FDA Advisers To Discuss Future Of COVID-19 Vaccine Boosters Wednesday
CNN (4/5, Howard) reports the Food and Drug Administration’s Vaccines and Related Biological Products Advisory Committee is “scheduled to meet Wednesday to get a clearer picture of what the future of Covid-19 booster shots might look like.” The advisers “will discuss the possible need for Covid-19 vaccine booster shots in the future, including the process for selecting variant-specific boosters and whether the Covid-19 vaccine could become an annual shot.” CNN adds, “No official vote is planned at the meeting, and there will be no discussion of any specific products applying for authorization or approval.”
There is also news on the treatment front. Sotrovimab, the monoclonal antibody widely used in Covid 19 patients with Omicron has been determined to be ineffective against BA2. Fortunately, it has a successor, bebtelovimab.
GSK-Vir’s COVID-19 Antibody Therapy No Longer Authorized Amid BA.2 Spread, FDA Announces
Reuters (4/5, Leo, Satija) reports the Food and Drug Administration “said on Tuesday GlaxoSmithKline and Vir Biotechnology’s antibody therapy was no longer authorized as a COVID-19 treatment, with data suggesting it was unlikely to be effective against the dominant Omicron sub-variant [BA.2] in the country.” Vir “in a filing with the Securities and Exchange Commission said the two companies were preparing a package of data to support the use of a higher dose of sotrovimab for the Omicron BA.2 sub-variant.”
The AP (4/5, Perrone) reports the FDA “announced that…sotrovimab is no longer authorized to treat patients in any U.S. state or territory.”
From The Medical Letter:
The investigational monoclonal antibody bebtelovimab (LY-CoV1404 – Lilly) has been granted an FDA Emergency Use Authorization (EUA) for IV treatment of mild to moderate COVID-19 in patients ≥12 years old who weigh ≥40 kg and are at high risk of progressing to severe disease, including hospitalization and death, and for whom alternative treatment options are unavailable or inappropriate. Bebtelovimab is active against the Omicron variant of SARS-CoV-2; sotrovimab (VIR-7831) is the only other monoclonal antibody currently available for treatment of COVID-19 that is active against Omicron.