ABSTRACT
Background: Emerging SARS-CoV-2 sublineages continue to cause serious COVID-19 disease, but most individuals have not received COVID-19 vaccine for >1 year. Assessment of long-term effectiveness of bivalent COVID-19 vaccines against circulating sublineages is important to inform the potential need for vaccination with updated vaccines. Methods: In this test-negative study at Kaiser Permanente Southern California, sequencing-confirmed BA.4/BA.5- or XBB-related SARS-CoV-2-positive cases during 9/1/2022-6/30/2023 were matched 1:3 to SARS-CoV-2-negative controls. We assessed mRNA-1273 bivalent relative (rVE) and absolute vaccine effectiveness (VE) compared to [≥]2 or 0 doses of original monovalent vaccine, respectively. Outcomes were BA.4/BA.5- or XBB-related infection, emergency department/urgent care (ED/UC) encounters, and hospitalization. Results: The rVE analysis included 20,966 cases and 62,898 controls. rVE (95%CI) against BA.4/BA.5 at 14-60 days and 121-180 days was 52.7% (46.9-57.8%) and 35.5% (-2.8%-59.5%) for infection, and 59.3% (49.7-67.0%) and 33.2% (-28.2-68.0%) for ED/UC encounters. For BA.4/BA.5-related hospitalizations, rVE was 71.3% (44.9-85.1%) and 52.0% (-1.2-77.3%) at 14-60 days and 61-120 days, respectively. rVE against XBB at 14-60 days and 121-180 days, was 48.8% (33.4-60.7%) and -3.9% (-18.1-11.3%) for infection, 70.7% (52.4-82.0%) and 15.7% (-6.0-33.2%) for ED/UC encounters, and 87.9% (43.8-97.4%) and 57.1% (17.0-77.8%) for hospitalization. Results for VE and subgroup analyses (age, immunocompromise, and previous SARS-CoV-2 infection) were similar to rVE analyses. Conclusions: rVE of mRNA-1273 bivalent vaccine against BA.4/BA.5 and XBB infections, ED/UC encounters, and hospitalizations waned over time. Periodic adjustment of vaccines to target emerging variants and revaccination may be important in reducing COVID-19 morbidity and mortality.
Subject(s)
COVID-19ABSTRACT
Introduction The potential association between bivalent COVID-19 vaccination and ischemic stroke remains uncertain, despite several studies conducted thus far. The purpose is to evaluate the risk of ischemic stroke following bivalent COVID-19 vaccination. Methods A self-controlled case series study was conducted among members aged 12 years and older who experienced ischemic stroke between September 1, 2022 and March 31, 2023 in a large California health care system. Ischemic strokes were identified using ICD-10 codes in Emergency Department and inpatient settings. Exposures were Pfizer-BioNTech or Moderna bivalent COVID-19 vaccination. Risk intervals were pre-specified as 1-21 days and 1-42 days after bivalent COVID-19 vaccination; all non-risk-interval person-time served as control interval. We conducted overall and subgroup analyses by age, history of SARS-CoV-2 infection, and co-administration of influenza vaccine. When an elevated risk was detected, we performed chart review of ischemic strokes, and re-evaluated the risk. RESULTS With 4933 cases, we found no increased risk within 21-day risk interval across vaccines and by subgroups. However, an elevated risk emerged within 42-day risk interval among individuals <65 years who received co-administration of Pfizer-BioNTech bivalent vaccine and influenza vaccine on the same day; relative incidence (RI) was 2.14 (95% CI, 1.02-4.49). Among those who also had history of SARS-CoV-2 infection, RI was 3.94 (95% CI, 1.10-14.16). After chart review, RIs were 2.35 (95% CI, 0.98-5.65) and 4.33 (95% CI, 0.98-19.11), respectively. Among individuals <65 years who received Moderna bivalent vaccine and had history of SARS-CoV-2 infection, RI was 2.62 (95% CI, 1.13-6.03) before chart review and 2.24 (95% CI, 0.78-6.47) after chart review. CONCLUSIONS The potential association between bivalent COVID-19 vaccination and ischemic stroke in the 1-42-day analysis warrants further investigation among individuals <65 years with influenza vaccine co-administration and prior SARS-CoV-2 infection.
Subject(s)
COVID-19 , Stroke , IschemiaABSTRACT
The bivalent (original and Omicron BA.4/BA.5) mRNA-1273 COVID-19 vaccine was authorized to offer broader protection against COVID-19. We conducted a matched cohort study to evaluate the effectiveness of the bivalent vaccine in preventing hospitalization for COVID-19 (primary outcome) and medically attended SARS-CoV-2 infection and hospital death (secondary outcomes). Compared to individuals who did not receive bivalent mRNA vaccination but received [≥]2 doses of any monovalent mRNA vaccine, the relative vaccine effectiveness (rVE) against hospitalization for COVID-19 was 70.3% (95% confidence interval, 64.0%-75.4%). rVE was consistent across subgroups and not modified by time since last monovalent dose or number of monovalent doses received. Protection was durable [≥]3 months after the bivalent booster. rVE against SARS-CoV-2 infection requiring emergency department/urgent care and against COVID-19 hospital death was 55.0% (50.8%-58.8%) and 82.7% (63.7%-91.7%), respectively. The mRNA-1273 bivalent booster provides additional protection against hospitalization for COVID-19, medically attended SARS-CoV-2 infection, and COVID-19 hospital death.
Subject(s)
Severe Acute Respiratory Syndrome , Death , COVID-19ABSTRACT
Studies have reported reduced natural SARS-CoV-2 infection- and vaccine-induced neutralization against Omicron BA.4/BA.5 compared with earlier Omicron subvariants. We conducted a test-negative case-control study evaluating mRNA-1273 vaccine effectiveness (VE) against infection and hospitalization with Omicron subvariants. The study included 30,809 SARS-CoV-2 positive and 92,427 SARS-CoV-2 negative individuals aged [≥]18 years tested during 1/1/2022-6/30/2022. While 3-dose VE against BA.1 infection was high and waned slowly, VE against BA.2, BA.2.12.1, BA.4, and BA.5 infection was initially moderate to high (61.0%-90.6% 14-30 days post third dose) and waned rapidly. The 4-dose VE against infection with BA.2, BA.2.12.1, and BA.4 ranged between 64.3%-75.7%, and was low (30.8%) against BA.5 14-30 days post fourth dose, disappearing beyond 90 days for all subvariants. The 3-dose VE against hospitalization for BA.1, BA.2, and BA.4/BA.5 was 97.5%, 82.0%, and 72.4%, respectively; 4-dose VE against hospitalization for BA.4/BA.5 was 88.5%. Evaluation of the updated bivalent booster is warranted.
Subject(s)
COVID-19ABSTRACT
Background: We conducted a prospective cohort study at Kaiser Permanente Southern California to study the vaccine effectiveness (VE) of mRNA-1273 over time and during the emergence of the Delta variant. Methods: The cohort for this planned interim analysis consisted of individuals aged [≥]18 years receiving 2 doses of mRNA-1273 through June 2021, matched 1:1 to randomly selected unvaccinated individuals by age, sex, and race/ethnicity, with follow-up through September 2021. Outcomes were SARS-CoV-2 infection, and COVID-19 hospitalization and hospital death. Cox proportional hazards models were used to estimate adjusted hazard ratios (aHR) with 95% confidence intervals (CIs) comparing outcomes in the vaccinated and unvaccinated groups. Adjusted VE (%) was calculated as (1-aHR)x100. HRs and VEs were also estimated for SARS-CoV-2 infection by age, sex, race/ethnicity, and during the Delta period (June-September 2021). VE against SARS-CoV-2 infection and COVID-19 hospitalization was estimated at 0-<2, 2-<4, 4-<6, and 6-<8 months post-vaccination. Results: 927,004 recipients of 2 doses of mRNA-1273 were matched to 927,004 unvaccinated individuals. VE (95% CI) was 82.8% (82.2-83.3%) against SARS-CoV-2 infection, 96.1% (95.5-96.6%) against COVID-19 hospitalization, and 97.2% (94.8-98.4%) against COVID-19 hospital death. VE against SARS-CoV-2 infection was similar by age, sex, and race/ethnicity, and was 86.5% (84.8-88.0%) during the Delta period. VE against SARS-CoV-2 infection decreased from 88.0% at 0-<2 months to 75.5% at 6-<8 months. Conclusions: These interim results provide continued evidence for protection of 2 doses of mRNA-1273 against SARS-CoV-2 infection over 8 months post-vaccination and during the Delta period, and against COVID-19 hospitalization and hospital death.
Subject(s)
COVID-19ABSTRACT
BackgroundVaccines may elicit long-term boosting of innate immune responses that can help protect against COVID-19. We evaluated the association between recombinant adjuvanted zoster vaccine (RZV) and COVID-19 outcomes at Kaiser Permanente Southern California. MethodsIn a cohort design, adults aged [≥]50 years who received [≥]1 RZV dose prior to 3/1/2020 were matched 1:2 to unvaccinated individuals and followed until 12/31/2020. Adjusted hazard ratios (aHR) and 95% confidence intervals (CIs) for COVID-19 outcomes were estimated using Cox proportional hazards regression. In a test-negative design, cases had a positive SARS-CoV-2 test and controls had only negative tests, from 3/1/2020-12/31/2020. Adjusted odds ratios (aOR) and 95% CIs for prior receipt of RZV were estimated using logistic regression. ResultsIn the cohort design, 149,244 RZV recipients were matched to 298,488 unvaccinated individuals. The aHRs (95% CI) for COVID-19 diagnosis and hospitalization were 0.84 (0.81-0.87) and 0.68 (0.64-0.74), respectively. In the test-negative design, 8.4% of 75,726 test-positive cases and 13.1% of 340,898 test-negative controls had received [≥]1 RZV dose. The aOR (95% CI) was 0.84 (0.81-0.86). ConclusionRZV vaccination was associated with a 16% lower risk of COVID-19 diagnosis and 32% lower risk of hospitalization, suggesting RZV elicits heterologous protection, possibly through trained immunity.