Similarity of Protection Conferred by Previous SARS-CoV-2 Infection and by BNT162b2 Vaccine: A 3-Month Nationwide Experience From Israel.

The worldwide shortage of vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection while the pandemic still remains uncontrolled has led many countries to the dilemma of whether or not to vaccinate previously infected persons. Understanding the level of protection conferred by previous infection compared with that of vaccination is important for policy-making. We analyzed an updated individual-level database of the entire population of Israel to assess the protection provided by both prior infection and vaccination in preventing subsequent SARS-CoV-2 infection, hospitalization with coronavirus disease 2019 (COVID-19), severe disease, and death due to COVID-19. Outcome data were collected from December 20, 2020, to March 20, 2021. Vaccination was highly protective, with overall estimated effectiveness of 94.5% (95% confidence interval (CI): 94.3, 94.7) for documented infection, 95.8% (95% CI: 95.2, 96.2) for hospitalization, 96.3% (95% CI: 95.7, 96.9) for severe illness, and 96.0% (95% CI: 94.9, 96.9) for death. Similarly, the overall estimated level of protection provided by prior SARS-CoV-2 infection was 94.8% (95% CI: 94.4, 95.1) for documented infection, 94.1% (95% CI: 91.9, 95.7) for hospitalization, and 96.4% (95% CI: 92.5, 98.3) for severe illness. Our results should be considered by policy-makers when deciding whether or not to prioritize vaccination of previously infected adults.

Fighting a pandemic: sociodemographic disparities and coronavirus disease-2019 vaccination gaps-a population study.

BACKGROUND: Data suggest lower coronavirus disease-2019 (COVID-19) vaccination coverage among minority and disadvantaged groups. We aimed to identify interactions between sociodemographic factors associated with vaccination gaps. METHODS: This population study used Israeli National COVID-19 data (extracted: 10 May 2021). The analysis comprised 6 478 999 individuals age ≥15 years with aggregated area-level data on sex and age distribution and no COVID-19 history. We estimated vaccination hazard and cumulative incidence using the Fine and Gray competing risk model. RESULTS: Older age and higher socioeconomic status (SES) were associated, with stepwise higher cumulative vaccination rates (age 20-24: 67%, age ≥ 75: 96%; SES 1-3: 61%, 4-5: 74.2%, 6-7: 82%, 8-10: 87%). We found the lowest vaccination rates in Arab (65%) and Ultra-Orthodox Jewish (54%) areas. SES modified the association in Arab neighbourhoods, with higher coverage than in the non-Orthodox Jewish reference group in SES 1-3 [adjusted hazard ratio (HR) = 1.06; 95% confidence interval (CI): 1.02-1.11], and gradually lower coverage in higher SES classes (SES 6-7: HR = 0.83; 95% CI: 0.79-0.87). Vaccination rates were also higher among younger Arabs (≤45 years) compared with age counterparts in the reference population group (age 25-34: HR = 1.18; 95% CI: 1.12-1.28) and lower than the reference group among Arabs age ≥45 years. Among Ultra-Orthodox Jews, vaccination HRs remained below one across age and SES classes. CONCLUSIONS: Age and SES modified the association between population group and vaccination coverage. Identifying the interplay between sociodemographic characteristics and the underlying explanations may improve targeted efforts, aimed at closing vaccination coverage gaps and mitigating COVID-19.

Decreased infectivity following BNT162b2 vaccination: A prospective cohort study in Israel.

BACKGROUND: BNT162b2 was shown to be 92% effective in preventing COVID-19. Prioritizing vaccine rollout, and achievement of herd immunity depend on SARS-CoV-2 transmission reduction. The vaccine's effect on infectivity is thus a critical priority. METHODS: Among all 9650 HCW of a large tertiary medical center in Israel, we calculated the prevalence of positive SARS-CoV-2 qRT-PCR cases with asymptomatic presentation, tested following known or presumed exposure and the infectious subset (N-gene-Ct-value<30) of these. Additionally, infection incidence rates were calculated for symptomatic cases and infectious (Ct<30) cases. Vaccine effectiveness within three months of vaccine rollout was measured as one minus the relative risk or rate ratio, respectively. To further assess infectiousness, we compared the mean Ct-value and the proportion of infections with a positive SARS-CoV-2 antigen test of vaccinated vs. unvaccinated. The correlation between IgG levels within the week before detection and Ct level was assessed. FINDINGS: Reduced prevalence among fully vaccinated HCW was observed for (i) infections detected due to exposure, with asymptomatic presentation (VE(i)=65.1%, 95%CI 45-79%), (ii) the presumed infectious (Ct<30) subset of these (VE(ii)=69.6%, 95%CI 43-84%) (iii) never-symptomatic infections (VE(iii)=72.3%, 95%CI 48-86%), and (iv) the presumed infectious (Ct<30) subset (VE(iv)=83.0%, 95%CI 51-94%).Incidence of (v) symptomatic and (vi) symptomatic-infectious cases was significantly lower among fully vaccinated vs. unvaccinated individuals (VE(v)= 89.7%, 95%CI 84-94%, VE(vi)=88.1%, 95%CI 80-95%).The mean Ct-value was significantly higher in vaccinated vs. unvaccinated (27.3±1.2 vs. 22.2±1.0, p<0.001) and the proportion of positive SARS-CoV-2 antigen tests was also significantly lower among vaccinated vs. unvaccinated PCR-positive HCW (80% vs. 31%, p<0.001). Lower infectivity was correlated with higher IgG concentrations (R=0.36, p=0.01). INTERPRETATION: These results suggest that BNT162b2 is moderately to highly effective in reducing infectivity, via preventing infection and through reducing viral shedding. FUNDING: Sheba Medical Center, Israel.