RR:C19 Evidence Scale rating by reviewer:
Potentially informative. The main claims made are not strongly justified by the methods and data, but may yield some insight. The results and conclusions of the study may resemble those from the hypothetical ideal study, but there is substantial room for doubt. Decision-makers should consider this evidence only with a thorough understanding of its weaknesses, alongside other evidence and theory. Decision-makers should not consider this actionable, unless the weaknesses are clearly understood and there is other theory and evidence to further support it.
This is a descriptive study published as a pre-print on the medXriv server. This is an analysis of mortality risks associated with young individuals (<=20 years) concerning low respiratory infections or LRI (2019) and COVID-19 (2020 and 2021). It concerns a relevant topic, particularly in Mexico, in terms of the current debate concerning vaccination of young people and the resume of school activities. Claims are potentially informative by the data and methods used, which could be easily improved by including more information, particularly aimed for non-epidemiologists.
As it is presented, the manuscript corresponds to a pure descriptive analysis since there are not comparisons through statistical tests, for instance between age groups or between years (COVID19 mortality in 2020 vs 2021), which perhaps could improve its overall presentation. In this sense, for instance, the inclusion in the graphs of the confidence intervals, which were obtained, could be useful. Additionally, it could be useful for non-experts in medical studies a little discussion concerning why and how LRI is important and can be compared with COVID-19 mortality. As it is, the reader is unable to understand why LRI for 2020 and 2021 mortality risks are not obtained, though it is evident that there could be confusion between COVID-19 and LRI mortality. Maybe this information is not even available, but this is not presented or discussed. Considering that several co-morbidities are highly associated with COVID-19 mortality, perhaps an analysis of how mortality has evolved from 2019 to 2020 and 2021 for other specific important diseases could help the reader to understand if mortality has changed only for LRI. In this sense, it is not completely clear whether the message of the manuscript is that LRI mortality changed because of the COVID19 pandemic, if so, it could make relevant a similar analysis for other diseases whose mortality changed as well.