Symptom and Age Homophilies in SARS-CoV-2 Transmission Networks during the First and Second Waves of the Pandemic in Japan (preprint)

Background Hokkaido is the northernmost, least populous, and coldest of the Japanese islands. It was the first prefecture to be affected by COVID-19, while Kanagawa is home to one of the most populous areas of Japan, namely the Tokyo metro area. The Japanese government responded early during the pandemic by identifying infected patients, contact tracing, and performing PCR analysis on anyone who was suspected of having been exposed to SARS-CoV-2. The government has also been publishing information about each individual who tested positive for the virus. Both Hokkaido and Kanagawa started recording COVID-19 cases in the winter of 2020 and have detailed records of thousands of patients, thus providing an invaluable resource for the transmission and behavior of the virus. Methods The current study analyzed the COVID-19 registry data from the Hokkaido and Kanagawa prefectures. The Hokkaido registry contained 1,269 cases (674 (53%) females and 595 (47%) males) recorded between February 14 and July 22, 2020. The Kanagawa registry had 3,123 cases (1,346 (43%) females and 1,777 (57%) males. The final data contained a total of 4,392 cases (2,020 (46%) females and 2,372 (54%) males). By leveraging the information on viral transmission paths available in the registry data, we performed exponential random graph model (ERGM) network analysis to examine demographic and symptomological homophilies of the SARS-CoV-2 viral transmission networks. Results We observed age, symptomatic, and asymptomatic homophilies in both prefectures. Furthermore, those patients who contracted the virus through secondary or tertiary contacts were more likely to be asymptomatic than those who contracted it from primary infection cases. The transmission networks showed that transmission occurred significantly in healthcare settings, as well as in families, although the size of the networks was small in the latter. Most of the transmissions stopped at the primary and secondary levels and no transmission beyond quaternary was observed. We also observed a higher level of asymptomatic transmission in Kanagawa than in Hokkaido. Conclusions Symptom homophilies are an important component of COVID-19 and suggest that nuanced genetic differences in the virus may affect its epithelial cell type range and can thus result in the diversity of symptoms seen in individuals infected by SARS-CoV-2. Moreover, environmental variables such as temperature and humidity may also be playing an important role in the overall pathogenesis of the virus.

Knowledge, attitudes and perceptions towards COVID-19 vaccinations: a cross-sectional community survey in Bangladesh (preprint)

BackgroundSeveral vaccines have been approved against coronavirus disease (COVID-19) and distributed globally in different regions. However, general community knowledge, attitudes and perceptions towards COVID-19 vaccinations are poorly understood. Thus, the study aimed to investigate community knowledge, attitudes and perceptions towards COVID-19 vaccinations in Bangladesh. MethodsAn exploratory and anonymous population-based e-survey was conducted among 1658 general individuals (55.6% male; mean age=23.17{+/-}6.05 years; age range=18-65 years). The survey was conducted using a semi-structured and self-reported questionnaire containing informed consent along with four sections (i.e., socio-demographics, knowledge, attitudes, and perceptions). Multiple linear regression was performed to determine the variables predicting knowledge, and attitudes towards COVID-19 vaccinations. ResultsThe mean scores of knowledge and attitudes were 2.83{+/-}1.48 (out of 5) and 9.34{+/-}2.39 (out of 12) respectively. About a quarter of participants thought that the COVID-19 vaccination available in Bangladesh is safe, only 60% will have the vaccination and about two-thirds will recommend it to family and friends. In the multiple regression model, higher SES, having university/ higher levels of education, holding nuclear families and having previous history of essential vaccines uptake were associated with knowledge; whilst attitudes were significantly associated with being female and having previous history of essential vaccines uptake. Just over half of the participants thought that everyone should be vaccinated and 61% responded that health workers should be vaccinated first on priority basis. 95% vaccine should be administered free of charge in Bangladesh and almost 90% believed that the COVID-19 vaccine used in Bangladesh may have side effects. ConclusionsThe findings reflect inadequate knowledge but more positive attitudes towards COVID-19 vaccine among the general population in Bangladesh. In order to improve knowledge, immediate health education programs need to be initiated before mass vaccination schedule.

The Impact of Differing COVID-19 Mitigation Policies: Three Natural Experiments (preprint)

This paper presents a comparison of the COVID-19 infections between a select pair of neighboring states and their border county regions where the policies of the Non-Pharmaceutical Interventions (NPI) such as Lockdown/Stay-at-Home differ. These analyses use a Difference-in-Differences (Diff-in Diff) model to test the effectiveness of NPI in mitigating COVID-19 infections at the state and border county regions between these states. The counties are in the states on the Iowa and Illinois border, the Dakotas (North and South) and Minnesota border and the Arkansas and Mississippi border. In each case the policies on each side of the border differ and the border is clearly designated by a river separation. Based on the Diff-in-Diff model output, state policies appear to make a significant difference in some of these specific border regions, at least early in the pandemic (April-June 2020). State level results are mixed reflecting spatial heterogeneity across the inter-state system.

Determinants of Voluntary Compliance: COVID-19 Mitigation (preprint)

During the pre-vaccine period, the success of containing the spread of COVID-19 depends upon how communities respond to non-pharmaceutical mitigation policies such as social distancing, wearing of masks, retail and dining constraints, crowd limitation, and shelter-in-place orders. Of these policies, shelter-in-place and social distancing are of central importance. By using county-level mobility data as a measure of a community’s voluntary compliance with social distancing policies, this study found that counties who received strong state social distancing policy directives and who had a high pro-social character showed lower mobility (better social distancing) after states reopened from shelter-in-place orders. Counties that experienced a longer duration of shelter-in-place orders showed higher mobility (less social distancing), implying that the duration of the shelter-in-place order deteriorated social distancing response after reopening. This may be because reopening sent a “safe” signal to these counties or resulted in a response to the pent-up demand inducing higher mobility. The results indicate that implementing shelter-in-place and social distancing policies to slow down the transmission of COVID-19 were not necessarily effective in motivating a county to reduce mobility voluntarily. A county’s pro-social character and the duration of shelter-in-place order should be considered when designing COVID-19 mitigation policies.

Regional Poverty Worsens Infectious Diseases: Evidence from COVID-19 Pandemic (preprint)

This paper examines the role of regional poverty on the COVID-19 pandemic in the U.S.A. It also verifies if the effects differ with the concentration of ethnic minorities. We find that poverty is a significant and consistent determinant of higher COVID-19 infections and fatalities. The prevalent poverty areas experienced higher infections due to its economic structures that require hypermobility - more physical human-to-human contacts and experienced higher deaths due to limited access to health services. These are also regions where minority groups are concentrated, and thus, the disproportionate infections and fatalities occurred within the black, Hispanic, and Asian population. Our evidence is robust to state fixed effects that capture local COVID-19 mitigation policies, multi-level hierarchical modeling, and large sets of county-level health, social, and economic factors. This paper contributes to the literature on health and economic disparities and their resulting consequences for infectious diseases.