To isolate or not to isolate: the impact of changing behavior on COVID-19 transmission.

BACKGROUND: The COVID-19 pandemic has caused more than 25 million cases and 800 thousand deaths worldwide to date. In early days of the pandemic, neither vaccines nor therapeutic drugs were available for this novel coronavirus. All measures to prevent the spread of COVID-19 are thus based on reducing contact between infected and susceptible individuals. Most of these measures such as quarantine and self-isolation require voluntary compliance by the population. However, humans may act in their (perceived) self-interest only. METHODS: We construct a mathematical model of COVID-19 transmission with quarantine and hospitalization coupled with a dynamic game model of adaptive human behavior. Susceptible and infected individuals adopt various behavioral strategies based on perceived prevalence and burden of the disease and sensitivity to isolation measures, and they evolve their strategies using a social learning algorithm (imitation dynamics). RESULTS: This results in complex interplay between the epidemiological model, which affects success of different strategies, and the game-theoretic behavioral model, which in turn affects the spread of the disease. We found that the second wave of the pandemic, which has been observed in the US, can be attributed to rational behavior of susceptible individuals, and that multiple waves of the pandemic are possible if the rate of social learning of infected individuals is sufficiently high. CONCLUSIONS: To reduce the burden of the disease on the society, it is necessary to incentivize such altruistic behavior by infected individuals as voluntary self-isolation.

Cost-benefit analysis of a rotavirus immunization program in the Arab Republic of Egypt.

BACKGROUND: The availability of rotavirus vaccines makes the implementation of a national immunization program an important decision requiring economic considerations. METHODS: A cost-benefit analysis of a national rotavirus immunization program in Egypt, from the perspective of the Ministry of Health and Population, and a cost-effectiveness analysis, from a societal perspective, were conducted. RESULTS: For a birth cohort of 1.9 million children, a vaccination program was estimated to prevent 1,140,496 episodes of diarrhea, 438,395 outpatient visits, and 47,508 hospitalizations and to save 2873 lives, resulting in direct Ministry of Health and Population medical savings of $2,481,792 (14,369,578 Egyptian pounds [LE]). On the basis of a $9.18 (53 LE) single-dose cost, rotavirus vaccine introduction would cost the Ministry of Health and Population $34,203,445.87 (198,037,951.56 LE) in health expenditures. This equates to an incremental cost of $30.22 (174.95 LE) per infection prevented. Vaccination would prevent the loss of 94,993 disability-adjusted life-years, resulting in an incremental cost-effectiveness ratio of $363 per disability-adjusted life-year. CONCLUSIONS: The introduction of rotavirus vaccine to the national immunization program was not found to be cost saving based strictly from the Ministry of Health and Population perspective; however, the potential benefits of long-term health and economic gains from reduced mortality and morbidity, decreased direct costs of care for families, and indirect societal costs should be considered in such decisions.

The impact of rotavirus vaccination on discounted net tax revenue in Egypt: a government perspective analysis.

BACKGROUND: We evaluated national rotavirus (RV) immunization programme costs to estimate how resulting changes in morbidity and mortality will influence government fiscal accounts over time. The assumption was that increased childhood survival in vaccinated cohorts leads to increased numbers of children consuming government resource, and an increased number of future tax payers. OBJECTIVE: Our objective was to evaluate the difference in lifetime discounted net tax revenue generated by RV vaccinated and unvaccinated cohorts from the Egyptian government perspective. METHODS: The model framework adopts the Egyptian government perspective for RV immunization costs (year 2009 values) and all government transfers (e.g. education costs, health costs, pensions). To reflect the government tax revenue, we applied a fixed income tax burden to earnings over the lifetime of vaccinated and unvaccinated cohorts. At each year of the model, we derive net taxes (gross taxes less transfers) discounted to the immunization year to reflect the present value of RV vaccination investment costs. RESULTS: Projected incremental net present values of the vaccinated cohort versus the unvaccinated cohort are $US6.1 million, $US58.1 million and $US55.7 million at 25-, 50- and 72-year time horizons, respectively. The internal rate of return for the government based on RV vaccination at years 25, 50 and 72 was 10.8%, 15.1% and 14.9, respectively. Within the first 5 years of vaccination, 76% of vaccine acquisition costs were offset due to direct and indirect cost savings attributed to a reduction in RV-related disease burden. Investments in RV vaccination in a single year are entirely offset when the vaccinated cohort of newborns reach 22 years of age. CONCLUSION: The government perspective is useful for evaluating investments in RV vaccination because of ongoing government transfers and tax receipts attributed to changes in RV-attributed morbidity and mortality. The analysis described here illustrates that investing in RV offers tangible long-term fiscal benefits for government over many generations that would not ordinarily be captured in economic evaluations typically applied to healthcare interventions.