The Omicron (B. 1.1. 529) wave in Mexico: Vaccine protection against progression to severe COVID-19 in SARS-CoV-2-infected workers (Preprint)

Abstract

BACKGROUND The use of administrative and public health surveillance data has been key to follow the Omicron wave during the COVID-19 pandemic. Mexico is among the countries with the most registered deaths during the pandemic and few studies in the region have focused on the effect that the Omicron wave had on hospitalization and death among workers. OBJECTIVE To assess the protection of 7 different COVID-19 vaccine products against progression to severe illness, using administrative and surveillance data of private-sector workers infected with SARS-CoV-2 during the Omicron wave in Mexico from January 2 to March 5, 2022. METHODS We conducted a retrospective cohort evaluation using Respiratory-Disease Short-Term Disability Claims (RD-STDC) registered by the Mexican Social Security Institute (IMSS), linked to COVID-19 surveillance system records and the national COVID-19 vaccination registry. Among all workers who requested RD-STDC and tested positive for SARS-CoV-2, we identified those who developed illness progression (hospitalization or death) attributable to respiratory disease. Vaccinated workers were those who had received the second of a two-dose COVID-19 vaccine series or a single dose of a one-dose product ≥14 days before a positive SARS-CoV-2 test result. We estimated risk ratios for disease progression by vaccination status using Poisson regression models adjusted for sex, age, past RD-STDC, self-reported comorbidities, income, state of residency, and weekly COVID-19 incidence (RRadj). RESULTS During January 2 to March 5, 2022, n=1,410,675 (7%) among 20.1 million private sector workers requested RD-STDC, of which 31.6% had a SARS-CoV-2 test and 445,404 (92.3%) tested positive. Of these workers, 38,676 (11.1%) were unvaccinated and 309,223 (88.9%) received a complete vaccination schedule ≥ 14 days before RD-STDC; 1,198 were hospitalized, and 187 died. Risk of both hospitalization and death were lower among vaccinated persons compared with unvaccinated persons; overall RRadj for hospitalization and death were 0.36 (95% CI 0.32–0.41) and 0.24 (0.17–0.33), respectively. By product, the RRadj for hospitalization was 0.27 (95% CI 0.22–0.33) for Pfizer BioNTech; 0.29 (95% CI 0.15–0.57) for Moderna; 0.32 (95% CI 0.25–0.41) for Sinovac; 0.39 (95% CI 0.34–0.46) for Astra Zeneca; 0.39 (95% CI 0.28–0.53) Sputnik; 0.41 (95% CI 0.24–0.7) for CanSino; and 0.53 (95% CI 0.39–0.72) for Janssen. The RRadj for death was 0.12 (95% CI 0.07–0.19) for Pfizer BioNTech; 0.15 (95% CI 0.06–0.38) for Sputnik; 0.29 (95% CI 0.16–0.53) for Sinovac; 0.30 (95% CI 0.20–0.44) for Astra Zeneca; 0.38 (95% CI 0.1–1.4) for CanSino; and 0.50 (95% CI 0.26–0.97) for Janssen. CONCLUSIONS COVID-19 vaccines were associated with a significant reduction in the risk for progression to severe illness during the Omicron wave in Mexico.

The Omicron wave in Mexico: vaccine protection against progression to severe Covid-19 in SARS-CoV-2-infected workers

“…Significant predictors for hospitalization/death were age, sex, diabetes, obesity, hypertension, and other comorbidities, salary, history of RD-STDC during years 2020 or 2021, state of residency, and epidemiological week (supplementary table S3). 22 Having received any of the evaluated vaccines within the recommended schedule significantly reduced the risk of progression to hospitalization or death (table II).…”

“…A greater percentage of workers in the analytical sample were vaccinated when compared to all workers with RD-STDC (88.9 vs. 83.6%, p<0.01), but otherwise were of similar age, sex, and salary (supplementary table S1). 22 Workers in the analytic sample had a mean age of 35.9 years (interquartile range [IQR] 27-44 years) and 46.7% were male, 88.9% were fully vaccinated and 11.1% were unvaccinated. Demographic characteristics such as age and state of residence differed by vaccine brand received (supplementary table S2).…”

“…Demographic characteristics such as age and state of residence differed by vaccine brand received (supplementary table S2). 22 In the cohort sample, a total of 1 198 workers were hospitalized and 187 died (table I). Among unvaccinated workers who filed for an RD-STDC, 7.4 per 1 000 were hospitalized and 1.5 per 1 000 died.…”

A Phase II Study Integrating a Single-Blind Safety Phase with a Double-Blind, Placebo-Controlled Randomized Phase, Assessing Single-Dose Intramuscular or Intranasal Administration to Evaluate the Safety and Immunogenicity of the Recombinant Vaccine Against COVID-19 (AVX/COVID-12 “Patria”) Based on an Active Newcastle Disease Viral Vector as a Heterologous Booster in Subjects with Evidence of Previous Immunity to SARS-CoV-2

“…Other studies indicate a 90.9% effectiveness of this vaccine against hospitalization and death caused by the Omicron BA.1 and BA.2 variants of SARS-CoV-2, while the AZ/ChAdOx-1-S vaccine showed 82.3% effectiveness (25). Moreover, COVID-19 vaccines available in Mexico have been reported to significantly reduce the risk of severe disease during the Omicron wave in the country (26).…”