To the Editor:
Knowledge are restricted relating to the effectiveness of the BNT162b2 vaccine (Pfizer–BioNTech) towards the BA.4 and BA.5 sublineages of the B.1.1.529 (omicron) variant of extreme acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that drove the current fifth wave of an infection in South Africa.1 We beforehand reported a vaccine effectiveness of 70% after two doses of the BNT162b2 vaccine towards extreme illness through the fourth wave of omicron an infection pushed by the BA.1 sublineage in South Africa.1,2
On this evaluation, we individually assessed the effectiveness and sturdiness of the BNT162b2 vaccine towards BA.1 or BA.2 and towards BA.4 or BA.5 amongst members of Discovery Well being, a medical care group that gives medical health insurance to three.7 million individuals in South Africa. Throughout the interval from November 15, 2021, to June 24, 2022, a complete of 32,883 sufferers who had been hospitalized for medical remedy underwent polymerase-chain-reaction testing for SARS-CoV-2, a interval that spanned the BA.1–BA.2 and BA.4–BA.5 omicron waves. Of those sufferers, 5909 (18.0%) have been discovered to be constructive for SARS-CoV-2 (Desk S4 within the Supplementary Appendix, obtainable with the complete textual content of this letter at NEJM.org).
On this inhabitants, we assessed the effectiveness of two doses and three doses (i.e., the unique two-dose collection plus a booster) of the BNT162b2 vaccine towards hospital admission for the remedy of attainable sequelae of coronavirus illness 2019 (Covid-19) in line with whether or not the BA.1 and BA.2 sublineages have been dominant (November 15, 2021, to February 28, 2022) or whether or not the BA.4 and BA.5 sublineages have been dominant (April 15 to June 24, 2022).1
We utilized a test-negative design and data-exclusion guidelines to acquire estimates of vaccine effectiveness. On this evaluation, we used a logistic-regression mannequin after adjustment for covariates to estimate vaccine effectiveness as 1 minus the percentages of vaccination amongst constructive circumstances. Vaccination standing was analyzed in line with the time that had elapsed for the reason that administration of the latest dose of vaccine (not vaccinated, 0 to 13 days, 14 to 27 days, 1 to 2 months, 3 to 4 months, 5 to six months, 7 to eight months, or ≥9 months).
Among the many sufferers who had obtained two doses of vaccine, waning of effectiveness towards hospitalization was evident as early as 3 to 4 months after vaccination throughout each durations when the omicron sublineages have been dominant. The vaccine effectiveness was 56.3% (95% confidence interval [CI], 51.6 to 60.5) through the BA.1–BA.2 wave and 47.4% (95% CI, 19.9 to 65.5) through the BA.4–BA.5 wave (Desk 1). Though boosting with a 3rd dose maintained vaccine effectiveness towards extreme illness brought on by all 4 sublineages at 1 to 2 months, the vaccine effectiveness had decreased by 3 to 4 months to an effectiveness of fifty.0% (95% CI, 4.4 to 73.9) through the BA.1–BA.2 wave and 46.8% (95% CI, 35.3 to 56.2) through the BA.4–BA.5 wave.
Thus, after both two doses or three doses of the BNT162b2 vaccine, we discovered fast waning of vaccine effectiveness towards the present sublineages of the omicron variant with respect to safety towards hospitalization. Our information point out that boosting maintains vaccine effectiveness towards extreme illness brought on by the present omicron sublineages, though the proof of fast waning of sturdiness signifies the necessity for normal boosting as early as 4 months after the final dose or the necessity for vaccines to include variants of concern to take care of safety.
Shirley Collie, B.Sc.
Jiren Nayager, B.Sc.
Discovery Well being, Sandton, South Africa
Lesley Bamford, M.B., Ch.B.
Nationwide Division of Well being, Pretoria, South Africa
Linda-Gail Bekker, M.B., Ch.B., Ph.D.
Desmond Tutu HIV Basis, Cape City, South Africa
Matt Zylstra, B.Sc.
Discovery Well being, Sandton, South Africa
Glenda Grey, M.B., B.Ch.
South African Medical Analysis Council, Cape City, South Africa
Disclosure kinds offered by the authors can be found with the complete textual content of this letter at NEJM.org.
This letter was revealed on September 14, 2022, at NEJM.org.
|Time since Most Latest Vaccine Dose||VE of Dose 2||VE of Dose 3|
|BA.1–BA.2 Omicron Wave||BA.4–BA.5 Omicron Wave||BA.1–BA.2 Omicron Wave||BA.4–BA.5 Omicron Wave|
|p.c (95% CI)|
|0–13 days||66.7 (38.3–82.0)||—||—||—|
|14–27 days||80.3 (62.8–89.5)||—||81.6 (68.1–89.4)||—|
|1–2 mo||61.3 (54.7–66.9)||—||66.4 (53.7–75.6)||68.8 (59.5–76.0)|
|3–4 mo||56.3 (51.6–60.5)||47.4 (19.9–65.5)||50.0 (4.4–73.9)||46.8 (35.3–56.2)|
|5–6 mo||45.6 (39.3–51.3)||26.3 (7.1–41.6)||—||—|
|7–8 mo||38.4 (16.9–54.4)||23.6 (11.1–34.3)||—||—|
|≥9 mo||—||19.3 (6.3–30.5)||—||—|