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

Abstract

Objective. To assess the effectiveness of seven Covid-19 vaccines in preventing disease progression (DP) using data from national private sector workers during the Omicron wave in Mexico from January 2 to March 5, 2022. Materials and methods. This study employed an administrative retrospective cohort design, analyzing DP (hospitalization or death due to respiratory disease) among workers who filed a respiratory short-term disability claim and tested positive for SARS-CoV-2. Risk ratios (RRadj) were estimated using Poisson regression models adjusted for various factors. Results. Vaccinated individuals had a lower risk of hospitalization and death compared with unvaccinated individuals. The overall RRadj for hospitalization and death were 0.36 (95%CI 0.32, 0.41) and 0.24 (0.17, 0.33), respectively. When evaluating vaccines individually, the RRadj for hospitalization were as follows Pfizer BioNTech 0.27 (95%CI 0.22, 0.33), Moderna 0.29 (95%CI 0.15, 0.57), Sinovac 0.32 (95%CI 0.25, 0.41), AstraZeneca 0.39 (95%CI 0.34, 0.46), Sputnik 0.39 (95%CI 0.28, 0.53), CanSino 0.41 (95%CI 0.24, 0.7), and Janssen 0.53 (95%CI 0.39, 0.72). The RRadj for death were as follows: Pfizer BioNTech 0.12 (95%CI 0.07, 0.19), Sputnik 0.15 (95%CI 0.06, 0.38), Sinovac 0.29 (95%CI 0.16, 0.53), AstraZeneca 0.30 (95%CI 0.20, 0.44), CanSino 0.38 (95%CI 0.1, 1.4), and Janssen 0.50 (95%CI 0.26, 0.97). Conclusion. Covid-19 vaccines significantly reduced the risk of severe disease during the Omicron wave in Mexico.

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).…”

Assessing the real-world effectiveness of five SARS-CoV-2 vaccines in a cohort of Mexican pensioners: a nationwide nested test-negative design study

“… 11 , 13 Acquiring a deeper understanding of real-world VE is especially important in Latin America, given that the pandemic was particularly severe there. 14 In Mexico, only a few studies have evaluated VE, and these studies have either focused on specific populations, such as non-essential workers 15 , 16 or individuals hospitalized because of COVID-19, 17 or relied exclusively on self-reported vaccination information, potentially limiting the accuracy of critical details, such as immunization dates. 9 …”