We would like to share ideas on the publication “Comparison of the effectiveness of four SARS-COV-2 vaccines in Nuevo Leon, Mexico: A test-negative control study.1” In Northeast Mexico, the four vaccines BNT162b2 (Pfizer-BioNTech), ChAdOx1 (AstraZeneca), Ad5-nCoV (CanSinoBIO), and CoronaVac (Sinovac Life Sciences) have been shown to be effective in lowering the odds of one primary outcome (symptomatic COVID-19 infection) and two secondary outcomes (hospitalization and severe COVID-19 infection).1

Regardless of sex or age, Salinas-Martnez et al. reported that Full immunization gave efficiency ranging from none to 75% (95%CI 71, 77) in lowering symptomatic COVID-19 infection.1 According to Salinas-Martnez et al., the completely BNT162b2 and ChAdOx1 schemes achieved their maximal effectiveness in terms of hospitalization and severity, respectively.1 To understand the results completely, a lot of things must be taken into account. Without the aid of specialized laboratory tests, a connection between asymptomatic COVID-19 and the lack of symptoms cannot be made. Asymptomatic COVID-19 and the lack of clinical symptoms could be misdiagnosed without the right laboratory tests. If neither the most recent clinical signals nor the most recent clinical markers are present, a silent COVID-19 must be ruled out.2 Due to other inherent genetic variations, some people's immune systems seem to respond to COVID-19 differently.3 The findings of the investigation need to be supported by additional clinical research. The findings of the investigation need to be supported by additional clinical research. Future research should, in case that it is possible, focus on the patient's genetic background, but it's also crucial to understand that some difficulties may have other origins.