Post-licensure safety study of new-onset immune-mediated diseases, herpes zoster, and anaphylaxis in adult recipients of HepB-CpG vaccine versus HepB-alum vaccine.

BACKGROUND: HepB-CpG (Heplisav-B) is a licensed hepatitis B vaccine with a novel adjuvant that requires 2 doses (0, 1 month) compared to HepB-alum (Engerix-B) which requires 3 doses (0, 1, 6 months). Monitoring safety outcomes following receipt of vaccines with novel adjuvants outside trial settings is important. Hence, as part of a post-marketing commitment, we compared the incidence of new-onset immune-mediated diseases, herpes zoster (HZ), and anaphylaxis among recipients of HepB-CpG versus HepB-alum. METHODS: This cohort study included adults not on dialysis who received ≥1 dose of hepatitis B vaccine from 8/7/2018 to 10/31/2019, during which HepB-CpG was routinely administered in 7 of 15 Kaiser Permanente Southern California medical centers while HepB-alum was administered in the other 8 centers. Recipients of HepB-CpG or HepB-alum were followed through electronic health records for 13 months for occurrence of pre-specified new-onset immune-mediated diseases, HZ, and anaphylaxis identified using diagnosis codes. Incidence rates were compared using Poisson regression with inverse probability of treatment weighting when there was ≥80 % power to detect a relative risk (RR) of 5 for anaphylaxis and RR of 3 for other outcomes. Chart review to confirm new-onset diagnosis was conducted for outcomes with statistically significant elevated risk. RESULTS: There were 31,183 HepB-CpG and 38,442 HepB-alum recipients (overall 49.0 % female, 48.5 % age ≥50 years, and 49.6 % Hispanic). Among immune-mediated events that occurred frequently enough for formal comparison, rates among HepB-CpG versus Hep-B-alum recipients were similar except for rheumatoid arthritis (RA) (adjusted RR 1.53 [95 % CI: 1.07, 2.18]). After chart confirmation of new-onset RA, the adjusted RR was 0.93 (0.34, 2.49). The adjusted RR for HZ was 1.06 (0.89, 1.27). Anaphylaxis occurred in 0 HepB-CpG and 2 HepB-alum recipients. CONCLUSIONS: This large post-licensure study did not identify evidence of safety concerns for HepB-CpG compared to HepB-alum for immune-mediated diseases, HZ, or anaphylaxis.

Effectiveness of a third dose of BNT162b2 mRNA COVID-19 vaccine in a large US health system: A retrospective cohort study.

Background: Globally, recommendations are expanding for third (booster) doses of BNT162b2 (Pfizer-BioNTech). In the United States, as of November 19, 2021, boosters were recommended for all adults aged 18 years and older. We evaluated the effectiveness of a third dose of BNT162b2 among adults in a large US integrated health system. Methods: In this retrospective cohort study, we analyzed electronic health records from Kaiser Permanente Southern California between Dec 14, 2020 and Dec 5, 2021 to assess vaccine effectiveness (VE) of two and three doses of BNT162b2 against SARS-CoV-2 infections (without hospital admission) andCOVID-19-related hospital admission. VE was calculated using hazards ratios from adjusted Cox models. Findings: After only two doses, VE against infection declined from 85% (95% CI 83-86) during the first month to 49% (46-51) ≥ 7 months following vaccination. Overall VE against hospitalization was 90% (95% CI 86-92) within one month and did not wane, however, effectiveness against hospitalization appeared to wane among immunocompromised individuals but was not statistically significant (93% [72-98] at 1 month to 74% [45-88] after ≥ 7 months; p=0·490). Three-dose VE (median follow-up 1·3 months [SD 0·6]) was 88% (95% CI 86-89) against infection and 97% (95-98) against hospitalization. Effectiveness after three doses was higher than that seen one month after receiving only two doses for both outcomes. Relative VE of three doses compared to two (with at least six months after the second dose) was 75% (95% CI 71-78) against infections and 70% (48-83) against hospital admissions. Interpretation: These data support the benefit of broad BNT162b2 booster recommendations, as three doses confers comparable, if not better, protection against SARS-CoV-2 infections and hospital admission as was seen soon after receiving two doses. Funding: Pfizer Inc.