Oral polio vaccine may play role against COVID-19

In a recent study published on medRxiv* preprint server, researchers performed an economic evaluation of oral polio vaccine (OPV) to illustrate the potential nonspecific (heterologous) effects (NSE) of live attenuated vaccines (LAVs).

Recent studies have reported that some vaccines have an NSE and can potentially provide protection against different pathogens. Although many economic evaluations analyze the specific pathogenic effects of vaccines, only two economic evaluations of the NSE were available. This study attempts to examine the NSE economic evaluations of OPV against coronavirus disease 2019 (COVID-19) and under-five mortality.

Study: A single vaccine to counter several diseases? Modeling the economics of oral polio vaccine against child mortality and COVID-19. Image Credit: frank60/Shutterstock

The study

The researchers assessed two settings: 1. Reduce child mortality in Guinea-Bissau, a high mortality setting where many previous studies, including randomized controlled trials, found that OPV reduced child morbidity and mortality by 10 at 36% and 2. COVID -19 prevention in India, a lower-middle-income country that is facing delays in the availability of the COVID-19 vaccine due to delays in development, production and supply chain. vaccine supply.

Regarding the reduction in child mortality, three annual campaigns were modeled in which all eligible children receive a dose of bivalent OPV every year for three years compared to a hypothetical cohort that did not receive the vaccine. Researchers analyzed a birth cohort of one million children in Guinea-Bissau with a mortality rate of 78 per 1,000 live births among children under five in 2019. It was assumed that all new -Borns received one standard dose of OPV at birth and three doses of OPV at 6, 10 and 14 weeks of age, along with other routine vaccinations.

In terms of COVID-19 prevention, the team developed a recovered susceptible-exposed-infectious model to measure the population benefits of two different scenarios where OPV would be co-administered with COVID-19 vaccines. Additionally, they adapted the model to more accurately reflect the transmission dynamics of COVID-19.

The researchers first expanded the “infectious” compartment to symptomatic, asymptomatic, hospitalized and intensive care to account for different levels of disease severity. Next, they created two more parallel sets of compartments for vaccinated people to reflect the reduced transmission and severity of COVID-19 after vaccination. To account for uncertainty and heterogeneity, they modeled benefit-cost ratios and incremental cost-effectiveness ratio for intervention effectiveness estimate ranges.

Results

For infant mortality, the results show that the overall cost-effectiveness ratio was $650 per child death averted. The benefit-cost ratio was 110 with a value per statistical life (VSL) of $71,000. Without the intervention, Guinea-Bissau’s age-specific death rates would be 50,000 among children aged 0-1, 6,650 deaths between 1-2 years, and 6,600 deaths between 2-3 years. The results showed that with the OPV intervention, the total number of deaths averted through the campaigns is 5,990, a 9.5% reduction in deaths compared to the numbers without the campaign.

The authors expect a higher number of deaths averted per 1000 campaign doses and lower cost-effectiveness with a higher under-five mortality rate and intervention efficacy. The cost-effectiveness or cost-benefit ratio may decrease with a lower mortality rate or intervention effectiveness.

OPV and COVID-19 vaccine given simultaneously t days after start of epidemic wave – additional impact on mortality, cost-effectiveness and cost-benefit of adding OPV A: additional deaths averted per 1000 people due to to adding OPV to the COVID-19 vaccine schedule only B: Incremental cost-effectiveness ratio per death averted of adding OPV to the COVID-19 vaccine schedule only C: Incremental benefit-cost ratio of adding the OPV to COVID-19 vaccine schedule only Results reflect scenario in which vaccination coverage for both vaccines are set at 30%. OPV is given simultaneously with the COVID-19 vaccine on day t. The COVID-19 vaccine is assumed to be 74% effective against infection and reduce infectiousness, 95% effective against severity, and requires 28 days from administration until it becomes fully effective. e = OPV vaccine efficacy against COVID-19.

For COVID-19, assuming 20% ​​OPV efficacy, the incremental cost was $23,000 to $65,000 for 58 deaths averted if OPV was given with a COVID-19 vaccine within 200 days of an outbreak. epidemic wave. At a 30% vaccination coverage rate, co-administration of OPV with the COVID-19 vaccine would result in a 13-35% reduction in COVID-19 infections and deaths if vaccines are administered before day 100, and a 2-13% reduction if vaccines are given between day 100 and 200, compared to the scenario where only COVID-19 vaccines are given.

In the event of a delay in the availability of COVID-19 vaccines, the cost per death averted would drop to $2,600-6,100. The estimated benefit-cost ratios were consistently high, although they varied considerably.

Conclusion

The results of the economic evaluation performed in this study highlight the potential of OPV to reduce child mortality in high mortality settings and its economically attractive role in preventing COVID-19. The results are consistent with previous and ongoing studies that have shown the high efficacy of VLAs in activating innate immune responses and reducing disease burden.

Current results show that VLAs such as OPV can be cost-effective and cost-effective interventions that can reduce child mortality. Although this evaluation shows the attractive potential of LAVs against COVID-19, this needs to be further investigated in trials.

*Important Notice

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be considered conclusive, guide clinical practice/health-related behaviors, or treated as established information.