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IntroductionRecent reviews summarize evidence that some vaccines have heterologous or non-specific effects (NSE), potentially offering protection against multiple pathogens. Numerous economic evaluations examine vaccines' pathogen-specific effects, but less than a handful focus on NSE. This paper addresses that gap by reporting economic evaluations of the NSE of oral polio vaccine (OPV) against under-five mortality and COVID-19.Materials and methodsWe studied two settings: (1) reducing child mortality in a high-mortality setting (Guinea-Bissau) and (2) preventing COVID-19 in India. In the former, the intervention involves three annual campaigns in which children receive OPV incremental to routine immunization. In the latter, a susceptible-exposed-infectious-recovered model was developed to estimate the population benefits of two scenarios, in which OPV would be co-administered alongside COVID-19 vaccines. Incremental cost-effectiveness and benefit-cost ratios were modeled for ranges of intervention effectiveness estimates to supplement the headline numbers and account for heterogeneity and uncertainty.ResultsFor child mortality, headline cost-effectiveness was $650 per child death averted. For COVID-19, assuming OPV had 20% effectiveness, incremental cost per death averted was $23,000-65,000 if it were administered simultaneously with a COVID-19 vaccine

The COVID-19 pandemic triggered an unparalleled pursuit of vaccines to induce specific adaptive immunity, based on virus-neutralizing antibodies and T cell responses. Although several vaccines have been developed just a year after SARS-CoV-2 emerged in late 2019, global deployment will take months or even years. Meanwhile, the virus continues to take a severe toll on human life and exact substantial economic costs. Innate immunity is fundamental to mammalian host defense capacity to combat infections. Innate immune responses, triggered by a family of pattern recognition receptors, induce interferons and other cytokines and activate both myeloid and lymphoid immune cells to provide protection against a wide range of pathogens. Epidemiological and biological evidence suggests that the live-attenuated vaccines (LAV) targeting tuberculosis, measles, and polio induce protective innate immunity by a newly described form of immunological memory termed "trained immunity." An LAV designed to induce adaptive immunity targeting a particular pathogen may also induce innate immunity that mitigates other infectious diseases, including COVID-19, as well as future pandemic threats. Deployment of existing LAVs early in pandemics could complement the development of specific vaccines, bridging the protection gap until specific vaccines arrive. The broad protection induced by LAVs would not be compromised by potential antigenic drift (immune escape) that can render viruses resistant to specific vaccines. LAVs might offer an essential tool to "bend the pandemic curve," averting the exhaustion of public health resources and preventing needless deaths and may also have therapeutic benefits if used for postexposure prophylaxis of disease.

The international response to the evolving Ebola epidemic in eastern Democratic Republic of Congo (DRC) has had interim successes while facing ongoing difficulties. The outbreak has occurred in an area of intractable conflict among multiple armed groups at a time of contentious national elections. Despite porous international borders and considerable population movement, however, transmission has been confined to North Kivu and Ituri provinces. Factors potentially contributing to this containment include conduct of about 55 million screenings, surveillance of contacts (12,591 under surveillance currently), testing of 280 samples per day, provision of safe and dignified burials for most deaths, vaccination of high-risk people (112,485 vaccinated as of May 7, 2019), and medical treatment including four investigational therapies. Major challenges remain. Since late February 2019, a sharp rise in cases and increased transmission have been observed. These coincide with organized attacks by armed groups targeting response teams, deteriorating security, and the population's increasing distrust of the response effort. The risk of local and regional spread remains high given the high proportion of deaths occurring outside treatment facilities, relatively low proportions of new patients who were known contacts, ongoing nosocomial transmission, and persistent delays in detection and reporting. Stopping this epidemic will require the alignment of the principal political and armed groups in eastern DRC in support of the response. [ABSTRACT FROM AUTHOR]