Effects of public health emergencies of international concern on disease control: a systematic review

Objectives. To assess the accumulated knowledge of the effects of public health emergencies of international concern on disease control and local health systems, and contribute to a better understanding of their effects on health programs and systems.Methods. This was a systematic review of published and gray literature (in English, Portuguese, or Spanish). Electronic databases (BVS/LILACS, PubMed, and SciELO) and Google Scholar were searched. Search terms were: COVID-19 OR H1N1 OR Ebola OR Zika OR poliomyelitis AND (outbreaks OR epidemics) AND (public health systems OR public health surveillance).Results. A total of 3 508 studies were retrieved, of which 31 met the inclusion criteria. The studies addressed the effects of the emergencies on: communicable diseases notification systems; malaria, HIV/AIDS, tubercu-losis, poliomyelitis, and malaria surveillance, control, and treatment; microcephaly; dengue; and vaccinations. The populations affected by the emergencies experienced reduced health services, which included fewer health visits, failures in the diagnostic chain, decrease in vaccination, and increased incidence or underreport-ing of notifiable diseases.Conclusions. Socioeconomic inequity is a determinant of the effects of public health emergencies of inter-national concern within affected populations. The diversion of resources and attention from health authorities disproportionately affects vulnerable populations and can lead, over time, to a weakening of health systems. The analysis of the effects of public health emergencies is important for the development of new protocols that can better respond to future crises.