Tracing and testing multiple generations of contacts to COVID-19 cases: cost-benefit trade-offs.

Traditional contact tracing tests the direct contacts of those who test positive. But, by the time an infected individual is tested, the infection starting from the person may have infected a chain of individuals. Hence, why should the testing stop at direct contacts, and not test secondary, tertiary contacts or even contacts further down? One deterrent in testing long chains of individuals right away may be that it substantially increases the testing load, or does it? We investigate the costs and benefits of such multi-hop contact tracing for different number of hops. Considering diverse contact networks, we show that the cost-benefit trade-off can be characterized in terms of a single measurable attribute, the initial epidemic growth rate. Once this growth rate crosses a threshold, multi-hop contact tracing substantially reduces the outbreak size compared with traditional tracing. Multi-hop even incurs a lower cost compared with the traditional tracing for a large range of values of the growth rate. The cost-benefit trade-offs can be classified into three phases depending on the value of the growth rate. The need for choosing a larger number of hops becomes greater as the growth rate increases or the environment becomes less conducive toward containing the disease.

Excess power at cellphone towers to sustain cold chain for COVID-19 and other vaccines in off-the-grid rural areas in India

Vaccines are the only currently available effective means to protect people from COVID-19 and reach herd immunity that restricts further spread of the disease. Vaccines require to be maintained in a cold chain which needs continuous electric power. While even the cities and large townships in the Indian power grid suffer from frequent power outages, a large number of areas are out of the grid and do not have the benefits of electric power. The poor and agrarian communities living in these areas need to be provided with vaccines as much as the urban populations that are being currently served. There are cellphone towers everywhere now, even in the off-grid areas. These towers have excess power which can be harnessed to run the cold chain in the off-grid places, as is being done in some African countries and Myanmar. The background, need and modalities for using power from the cellphone towers to run the vaccine cold chain in the off-grid areas, in the interests of rendering social justice, are discussed in this article. [ FROM AUTHOR] Copyright of Current Science (00113891) is the property of Indian Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Countering the potential re-emergence of a deadly infectious disease-Information warfare, identifying strategic threats, launching countermeasures.

OBJECTIVES: Eradicated infectious diseases like smallpox can re-emerge through accident or the designs of bioterrorists, and cause heavy casualties. Presently, the populace is largely susceptible as only a small percentage is vaccinated, and their immunity is likely to have waned. And when the disease re-emerges, the susceptible individuals may be manipulated by disinformation on Social Media to refuse vaccines. Thus, a combination of countermeasures consisting of antiviral drugs and vaccines and a range of policies for their application need to be investigated. Opinions regarding whether to receive vaccines evolve over time through social exchanges via networks that overlap with but are not identical to the disease propagation networks. These couple the spread of the biological and information contagion and necessitate a joint investigation of the two. METHODS: We develop a computationally tractable metapopulation epidemiological model that captures the joint spatio-temporal evolution of an infectious disease (e.g., smallpox, COVID-19) and opinion dynamics. RESULTS: Considering smallpox, the computations based on the model show that opinion dynamics have a substantial impact on the fatality count. Towards understanding how perpetrators are likely to seed the infection, we identify a) the initial distribution of infected individuals that maximize the overall fatality count; and b) which habitation structures are more vulnerable to outbreaks. We assess the relative efficacy of different countermeasures and conclude that a combination of vaccines and drugs minimize the fatalities, and by itself, drugs reduce fatalities more than the vaccine. Accordingly, we assess the impact of increase in the supply of drugs and identify the most effective among a collection of policies for administering of drugs for various parameter combinations. Many of the observed patterns are stable to variations of a diverse set of parameters. CONCLUSIONS: Our findings provide a quantitative foundation for various important elements of public health discourse that have largely been conducted qualitatively.