Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron (B.1.1.529) variant is highly transmissible with potential immune escape. We conducted a test-negative case–control study to evaluate mRNA-1273 vaccine effectiveness (VE) against infection and hospitalization with Omicron or Delta. The large, diverse study population included 26,683 SARS-CoV-2 test-positive cases with variants determined by S gene target failure status (16% Delta and 84% Omicron). The two-dose VE against Omicron infection at 14–90 days was 44.0% (95% confidence interval, 35.1–51.6%) but declined quickly. The three-dose VE was 93.7% (92.2–94.9%) and 86.0% (78.1–91.1%) against Delta infection and 71.6% (69.7–73.4%) and 47.4% (40.5–53.5%) against Omicron infection at 14–60 days and >60 days, respectively. The three-dose VE was 29.4% (0.3–50.0%) against Omicron infection in immunocompromised individuals. The three-dose VE against hospitalization with Delta or Omicron was >99% across the entire study population. Our findings demonstrate high, durable three-dose VE against Delta infection but lower effectiveness against Omicron infection, particularly among immunocompromised people. However, three-dose VE of mRNA-1273 was high against hospitalization with Delta and Omicron variants.

Objectives To evaluate the effectiveness of the mRNA-1273 vaccine against SARS-CoV-2 variants and assess its effectiveness against the delta variant by time since vaccination. Design Test negative case-control study. Setting Kaiser Permanente Southern California (KPSC), an integrated healthcare system. Participants Adult KPSC members with a SARS-CoV-2 positive test sent for whole genome sequencing or a negative test from 1 March 2021 to 27 July 2021. Interventions Two dose or one dose vaccination with mRNA-1273 (Moderna covid-19 vaccine) ≥14 days before specimen collection versus no covid-19 vaccination. Main outcome measures Outcomes included infection with SARS-CoV-2 and hospital admission with covid-19. In pre-specified analyses for each variant type, test positive cases were matched 1:5 to test negative controls on age, sex, race/ethnicity, and specimen collection date. Conditional logistic regression was used to compare odds of vaccination among cases versus controls, with adjustment for confounders. Vaccine effectiveness was calculated as (1–odds ratio)×100%. Results The study included 8153 cases and their matched controls. Two dose vaccine effectiveness was 86.7% (95% confidence interval 84.3% to 88.7%) against infection with the delta variant, 98.4% (96.9% to 99.1%) against alpha, 90.4% (73.9% to 96.5%) against mu, 96-98% against other identified variants, and 79.9% (76.9% to 82.5%) against unidentified variants (that is, specimens that failed sequencing). Vaccine effectiveness against hospital admission with the delta variant was 97.5% (92.7% to 99.2%). Vaccine effectiveness against infection with the delta variant declined from 94.1% (90.5% to 96.3%) 14-60 days after vaccination to 80.0% (70.2% to 86.6%) 151-180 days after vaccination. Waning was less pronounced for non-delta variants. Vaccine effectiveness against delta infection was lower among people aged ≥65 years (75.2%, 59.6% to 84.8%) than those aged 18-64 years (87.9%, 85.5% to 89.9%). One dose vaccine effectiveness was 77.0% (60.7% to 86.5%) against infection with delta. Conclusions Two doses of mRNA-1273 were highly effective against all SARS-CoV-2 variants, especially against hospital admission with covid-19. However, vaccine effectiveness against infection with the delta variant moderately declined with increasing time since vaccination.

Background The recently emerged SARS-CoV-2 omicron variant raised concerns around potential escape from vaccine-elicited immunity. Limited data are available on real-world vaccine effectiveness (VE) of mRNA-1273 against omicron. Here, we report VE of 2 or 3 mRNA-1273 doses against infection and hospitalization with omicron and delta, including among immunocompromised individuals. Methods This test negative study was conducted at Kaiser Permanente Southern California. Cases were individuals aged ≥18 years testing positive by RT-PCR with specimens collected between 12/6/2021 and 12/23/2021 with variant determined by spike gene status. Randomly sampled test negative controls were 5:1 matched to cases by age, sex, race/ethnicity, and specimen collection date. Conditional logistic regression models were used to evaluate adjusted odds ratio (aOR) of vaccination with mRNA-1273 doses between cases and controls. VE(%) was calculated as (1-aOR)x100. Results 6657 test positive cases (44% delta, 56% omicron) were included. The 2-dose VE against omicron infection was 30.4% (95% CI, 5.0%-49.0%) at 14-90 days after vaccination and declined quickly thereafter. The 3-dose VE was 95.2% (93.4%-96.4%) against delta infection and 62.5% (56.2%-67.9%) against omicron infection. The 3-dose VE against omicron infection was low among immunocompromised individuals (11.5%; 0.0%-66.5%). None of the cases (delta or omicron) vaccinated with 3 doses were hospitalized compared to 53 delta and 2 omicron unvaccinated cases. Conclusions VE of 3 mRNA-1273 doses against infection with delta was high and durable, but VE against omicron infection was lower. VE against omicron infection was particularly low among immunocompromised individuals. No 3-dose recipients were hospitalized for COVID-19.

Consideration of self-protection (rather than absolute disease risk or protection of patients) appears the strongest and most consistent driver of healthcare workers' decisions to accept vaccination, though other factors may also be impactful, and reasons for between-study divergence in effects is an important area for future research. This finding has important implications for the design of programs to enhance healthcare worker vaccine uptake.

Objectives Systemic vasculitis is often mistakenly assumed to be a common cause of retinal vasculitis. We sought to determine the relationship between retinal vasculitis and systemic vasculitis. Methods A selected review was performed on 1390 charts of patients attending the uveitis clinic at the Oregon Health & Science University between 1985 and 2010. Included in the review were all patients with diagnoses commonly associated with retinal vasculitis and all patients who were diagnosed with a systemic vasculitis. Retinal vasculitis was identified by perivascular exudates, intraretinal hemorrhage, or cotton wool spots as seen on clinical examination or by vascular occlusion or leakage as identified by fluorescein angiogram. Results 207 or 14.9% of patients with uveitis had retinal vasculitis as a component of the intraocular inflammation. Thirty-five patients had retinal vasculitis which was primary, i.e. not associated with a systemic disease, and the dominant manifestation of the uveitis. Fourteen of the patients with retinal vasculitis had Behcet’s disease. Only 11 of the 1390 patients with uveitis had a systemic vasculitis. Of these 11, four had retinal vasculitis including one secondary to a CMV retinitis. Thus, systemic vasculitis was directly responsible for 1.4% or 3 of 207 cases of retinal vasculitis. No-vasculitic systemic diseases such as sarcoidosis (n=13), syndromes confined to the eye such as pars planitis (n=36), and intraocular infections (n=29) were far more common causes of retinal vasculitis. Conclusion Retinal vasculitis is a relatively common feature of uveitis. Patients with retinal vasculitis, however, rarely suffer from one of the classical systemic vasculitides.