Explanations for higher-than-expected mortality from April 2021: a scoping review

ObjectivesMany countries have continued to experience a higher-than-expected number of deaths following the peaks in mortality observed in the first year of the Covid-19 pandemic. This scoping review aims to identify the different explanations proposed for sustained higher-than-expected mortality beyond the first pandemic year. Study designScoping review MethodsA systematic search of databases and grey literature sources was completed to identify English-language records proposing or investigating hypotheses for higher-than-expected mortality from April 2021 onwards in (sub)populations of high-income countries. Papers focused on survival following a diagnosis or intervention were excluded. Results were summarised narratively, and existing research prioritisation frameworks were adapted and applied to identify the hypotheses proposed as highest priority for further research. ResultsSeventy eligible papers were identified. Most were opinion pieces or simply presented trends; few included investigation of suggested hypotheses. Numerous explanations for higher-than-expected mortality were proposed, with hypotheses relating to direct Covid-19 mortality, sequalae of Covid-19 infection, the health service impacts of the pandemic, wider pandemic impacts and socioeconomic factors identified as highest-priority for further research. ConclusionsThe causes of continued higher-than-expected mortality are likely to be multiple and potentially interactive. This review will help to shape research into current mortality trends, with a critical understanding of this topic essential for achieving evidence-informed policy.