Vaccine Effectiveness, School Reopening, and Risk of Omicron Infection Among Adolescents Aged 12-17 Years.

PURPOSE: The BNT162b2 (Pfizer-BioNTech) is approved for adolescents aged 12-17 years. We estimated BNT162b2 vaccine effectiveness (VE) and a booster dose effectiveness in adolescents aged 12-17 years and the impact of opening schools and the Omicron variant on risk of SARS-CoV-2 infection in adolescents. METHODS: We used logistic regression with a test-negative design controlling for gender and race to estimate BNT162b2 VE and the effectiveness of a booster dose in adolescents aged 12-17 years. To evaluate the effect of school opening on Omicron transmission, we used Cox proportional hazards regression to compare adolescents to a reference group of adults aged 22-33 or aged 65+ years, investigating whether risk for adolescents increased relative to the reference group after school opened. RESULTS: We found that adolescents who received two BNT162b2 doses had significant protection against Omicron infection in the first three months following their second dose (VE = 54.5%, confidence interval [CI]: [17.8%-76.9%], p = .014) but no protection afterwards. Receiving a booster dose was associated with lower risk of infection (odds ratio = 0.48, CI: [0.33-0.69], p < .0001) and restored efficacy to a similar level (VE = 56.3%, CI: [36.5%-70.6%], p < .0001). We observed a statistically significant increase (p = .04) in adolescent infection risk relative to adults in the period of Omicron predominance. DISCUSSION: The BNT162b2 vaccine is effective at preventing SARS-CoV-2 infection in adolescents but immunity against Omicron wanes rapidly and booster doses are needed to retain protection. More research is needed to determine the effect of school reopening on spread in the Omicron-dominant period.

COVID-19 vaccine effectiveness against omicron (B.1.1.529) variant infection and hospitalisation in patients taking immunosuppressive medications: a retrospective cohort study.

Background: There is a scarcity of research regarding the effectiveness of the mRNA-1273 (Moderna) and BNT162b2 (Pfizer-BioNTech) COVID-19 vaccines in patients taking immunosuppressant medications, and no data are published to date pertaining to their effectiveness against omicron (B.1.1.529) variant SARS-CoV-2 infection and hospitalisation. We aimed to assess the relationship between immunosuppressive medications, mRNA vaccination, omicron infection, and severe COVID-19 outcomes (ie, hospitalisation, ICU admission, death). Methods: We did a retrospective cohort study and included vaccinated and unvaccinated people aged 18 years or older in the Michigan Medicine health-care system, USA, during the omicron-dominant period of the pandemic (Dec 16, 2021-March 4, 2022). We collected data from electronic health records (demographics, diagnoses, medications) combined with immunisation data from the Michigan State Registry to determine vaccination status, and we collected COVID-19-related hospitalisation data by chart review. We used a Cox proportional hazards model based on calendar time to assess the effectiveness of the mRNA-1273 and BNT162b2 vaccines in people taking immunosuppressive medications (conventional synthetic disease-modifying antirheumatic drugs [DMARDs], biologic DMARDs, or glucocorticoids within the past 3 months), while controlling for participant characteristics. Using the same model, we assessed the effect of different classes of medication such as immunosuppressive DMARDs, immunomodulatory DMARDs, and glucocorticoids on SARS-CoV-2 infection and hospitalisation due to COVID-19. All analyses were done using complete cases after removing participants with missing covariates. Findings: 209 492 people were identified in Michigan Medicine, including 165 913 who were vaccinated and 43 579 who were unvaccinated. 41 078 people were excluded because they were younger than 18 years, partially vaccinated, had received a vaccine other than the two vaccines studied, or had incomplete covariate data. 168 414 people were included in the analysis; 97 935 (58%) were women, 70 479 (42%) were men, and 129 816 (77%) were White. 5609 (3%) people were taking immunosuppressive medications. In patients receiving immunosuppressants, three doses of BNT162b2 had a vaccine effectiveness of 50% (95% CI 31-64; p<0·0001) and three doses of mRNA-1273 had a vaccine effectiveness of 60% (42-73; p<0·0001) against SARS-CoV-2 infection. Three doses of either vaccine had an effectiveness of 87% (95% CI 73-93; p<0·0001) against hospitalisation due to COVID-19. Receipt of immunosuppressive DMARDs (hazard ratio 2·32, 95% CI 1·23-4·38; p=0·0097) or glucocorticoids (2·93, 1·77-4·86; p<0·0001) and a history of organ or bone marrow transplantation (3·52, 2·01-6·16; p<0·0001) were associated with increased risk of hospitalisation due to COVID-19 compared with those who had not received immunosuppressive medications or transplant. Interpretation: People taking immunosuppressive DMARDs or glucocorticoids are at substantially higher risk of hospitalisation due to COVID-19 than the general population. However, the mRNA-1273 and BNT162b2 vaccines remain effective within this group, and it is important that patients taking these medications remain up to date with vaccinations to mitigate their risk. Funding: National Institute of Allergy and Infectious Diseases, National Institutes of Health.

Comparative Effectiveness of Coronavirus Disease 2019 (COVID-19) Vaccines Against the Delta Variant.

BACKGROUND: There is a lack of data regarding how the Delta variant of coronavirus disease 2019 (COVID-19) has impacted the effectiveness of the BNT162b2 (Pfizer-BioNTech), mRNA-1273 (Moderna), and Ad26.COV2.S (Johnson & Johnson-Janssen) vaccines at preventing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and COVID-19 hospitalization. METHODS: We compared the effectiveness of the three vaccines during the pre- and post-Delta variant period (before and after 1 July 2021) in a large cohort of vaccinated and unvaccinated patients in the Michigan Medicine healthcare system. We assessed vaccine effectiveness (VE) using 2 analyses: an inverse propensity weighted (IPW) Kaplan-Meier (KM) analysis based on time from vaccination, and a Cox model based on calendar time with vaccination as a time-varying covariate. RESULTS: Compared to Ad26.COV2.S recipients, the risk of hospitalization for COVID-19 in the post-Delta variant period was lower for BNT162b2 recipients (hazard ratio [HR] = 0.37; 95% confidence interval [CI]: [.14-.98]; P = .05) and mRNA-1273 recipients (HR = 0.21; 95% CI: [.07-.64]; P = .006). Recipients of the mRNA-1273 vaccine had a lower risk of SARS-CoV-2 infection than Ad26.COV2.S recipients (HR = 0.6; 95% CI: [.43-.83]; P = .003) and BNT162b2 recipients (HR = 0.64; 95% CI: [.54-.76]; P < .001). After 1 July, efficacy against SARS-CoV-2 infection declined for Ad26.COV2.S recipients (VE = 76% before; VE = 49% after; P = .02), BNT162b2 recipients (VE = 87% before; VE = 52% after; P < .001), and mRNA-1273 recipients (VE = 92% before; VE = 70% after; P < .001). Waning immunity and the Delta variant contributed independently and significantly to this decline. CONCLUSIONS: Although there is a substantial decline in effectiveness, the approved COVID-19 vaccines remain effective against infection and hospitalization due to the Delta variant. The mRNA-based vaccines are more effective than the Ad26.COV2.S vaccine.

Efficacy of COVID-19 vaccines in patients taking immunosuppressants.

OBJECTIVES: We intended to assess the effectiveness of all three US Food and Drug Administration approved COVID-19 vaccines at preventing SARS-CoV-2 infection and COVID-19 hospitalisation in a large cohort of individuals on immunosuppressants for a diverse range of conditions. METHODS: We studied the effectiveness of BNT162b2 (Pfizer-BioNTech), mRNA-1273 (Moderna) and Ad26.COV2.S (Johnson & Johnson-Janssen) vaccines among individuals who take immunosuppressants (including disease-modifying antirheumatic drugs and glucocorticoids) by comparing vaccinated (n=97688) and unvaccinated (n=42094) individuals in the Michigan Medicine healthcare system from 1 January to 7 December 2021, using Cox proportional hazards modelling with time-varying covariates. RESULTS: Among vaccinated and unvaccinated individuals, taking immunosuppressants increased the risk of SARS-CoV-2 infection (adjusted HR (aHR)=2.17, 95% CI 1.69 to 2.79 for fully vaccinated and aHR=1.40, 95% CI 1.07 to 1.83 for unvaccinated). Among individuals taking immunosuppressants, we found: (1) vaccination reduced the risk of SARS-CoV-2 infection (aHR=0.55, 95% CI 0.39 to 0.78); (2) the BNT162b2 and mRNA-1273 vaccines were highly effective at reducing the risk of SARS-CoV-2 infection (n=2046, aHR=0.59, 95% CI 0.38 to 0.91 for BNT162b2; n=2064, aHR=0.52, 95% CI 0.33 to 0.82 for mRNA-1273); (3) with a smaller sample size (n=173), Ad26.COV2.S vaccine protection did not reach statistical significance (aHR=0.34, 95% CI 0.09 to 1.30, p=0.17); and (4) receiving a booster dose reduced the risk of SARS-CoV-2 infection (aHR=0.42, 95% CI 0.24 to 0.76). CONCLUSIONS: The mRNA-1273 and BNT162b2 vaccines are effective in individuals who take immunosuppressants. However, individuals who are vaccinated but on immunosuppressants are still at higher risk of SARS-CoV-2 infection and COVID-19 hospitalisation than the broader vaccinated population. Booster doses are effective and crucially important for individuals on immunosuppressants.