Side effect of a 6 p.m curfew for preventing the spread of SARS-CoV-2: A modeling study from Toulouse, France

Changes in substance use among adolescents before and during the COVID-19 pandemic in Guatemala

Objectives

Due to the COVID-19 pandemic, on March 16th, schools had to be closed in Guatemala and went to online teaching. We sought to analyze the change in substance use among high school students in Guatemala associated with the lockdown.

Methods

Data from two surveys (2019, n=2096, and 2020, n=1606) of a student cohort in private high schools in Guatemala City was used. Logistic models for past 30-day cigarette, e-cigarette, marijuana, and alcohol (including binge drinking) were used, regressing these on survey wave, while adjusting for sex, scholastic performance, high school year of student, parental education, substance use, and household member tobacco use.

Results

Prevalence declined for smoking (10% to 3%, p<0.001), e-cigarette (31% to 14%, p<0.001), marijuana (4.3% to 1.9%, p<0.001), and alcohol use (47% to 38.5%, p<0.001), and binge drinking (24% to 13%, p<0.001). Adjusted models showed wave 2 associated with lower odds of using cigarettes (AOR=0.44, 95%CI=0.32-0.62), e-cigarettes (AOR=0.41, 95% CI=0.35-0.49, p<0.001), and binge drinking (AOR=0.73, 95%CI=0.59-0.89; p=0.002).

Conclusion

Among Guatemalan adolescents, COVID-19 restrictions were associated with a significant decrease in smoking, e-cigarette use, and binge drinking.

The effect of a nighttime curfew on the spread of COVID-19

While nighttime curfews are less severe restrictions compared to around-the-clock curfews in mitigating the spread of Covid-19, they are nevertheless highly controversial, with the scarce literature on their effectiveness providing mixed evidence. We study the effectiveness of the nighttime curfew in Hamburg, Germany's second largest city, in mitigating the spread of Covid-19. This curfew forbid people from leaving their home between 9 p.m. and 5 a.m. for non-essential businesses. Applying both difference-in-differences and synthetic control methods, we find that the curfew was effective in reducing the number of Covid-19 cases. As it is unclear whether and how the virus will mutate in the next time, policy-makers might have to resort to non-pharmaceutical interventions again. Nighttime curfews should be kept in the toolbox of policy-makers to fight Covid-19.

Measuring the effect of COVID-19-related night curfews in a bundled intervention within Germany

We estimate the impact of local night curfews in Hesse, the fifth most populous federal state in Germany, on the growth of incidences of COVID-19 cases residing within the "second wave" of the pandemic. Thereby, we take advantage of the fact that all counties had the same measures in place with the only difference that some additionally had to implement night curfews due to state regulations. This allows us to identify the effect of night curfews as a salient part of a bundled intervention. In our case where different other measures are already in place, night curfews had at best a limited effect in slowing down the spread of the pandemic. The effect is not significantly different from zero.

COVID-19: Early evening curfews and mobility

During the COVID-19 pandemic, some countries introduced early evening curfews. Several studies try to measure the effectiveness of such measures across different countries, but disentangling competing effects can be elusive. We examined the impact of an early evening curfew on mobility by studying a shift in curfews from 9pm to 6pm in Greece using Google mobility data. We followed a difference-in-differences (DiD) econometric approach, where we compared trends in mobility in residential spaces as well as groceries and pharmacies, before and after the introduction of the 6pm curfew in Attica with trends in three other comparable Regions. We found little or no evidence of an effect of the early curfew on daily mobility relating to groceries and pharmacies, and that an 18.75% reduction in hours where people were allowed to leave home led to a relatively small increase in time spent in residential spaces. This less-than-proportionate reduction in mobility outside the household suggests a possibility that the curfew led to more people coinciding in indoor public spaces, such as grocery shops - which constitutes a contagion risk factor. Results should be treated with caution, especially with regards to the magnitude of any effect, as Google mobility data do not report the time of the day, so the time density of activities cannot be estimated. Lockdowns and other measures are necessary to tackle Covid-19, but it is important to avoid substitution by activities that contribute further to spreading the virus. Interventions should therefore be based on a thorough analysis of human behaviour.

Good night: Experimental evidence that nighttime curfews may fuel disease dynamics by increasing contact density

Background

Nighttime curfews have been discussed and implemented in many countries as a means of controlling the COVID-19 pandemic. However, there is evidence that such curfews have little or no effect on disease dynamics when other measures such as bans on gatherings or business and school closures are already in place. There are two possible explanations for this. First, nighttime curfews may elicit reactance—a feeling of anger that drives non-adherence; second, nighttime curfews may motivate people to shift activities from night to daytime, thereby increasing contact density.

Methods

A survey experiment was conducted with German participants (N = 997) to investigate public perceptions of nighttime curfews and possible detrimental effects on contact behaviors.

Results

Most participants perceived nighttime curfews as ineffective. The introduction of a hypothetical curfew did not affect intentions to reduce private contacts but instead elicited reactance, motivating participants to violate curfew hours or to shift a fictitious dinner meeting to an earlier time rather than cancelling it.

Conclusions

When people do not support nighttime curfews or do not understand the rationale behind them, introduction of this measure may fuel the spread of the disease. For that reason, nighttime curfews should be a measure of last resort and should be accompanied by a public communication campaign explaining the importance of contact reduction during both nighttime and daylight hours.

Impact of a Single-Day Lockdown on COVID-19: An Interrupted Time Series Analysis

This study evaluated a special form of lockdown that was applied in Jordan: one day of lockdown every week, which was applied on consecutive weekend days (i.e., Friday in Jordan, for 24 hours). We tried to assess the impact of this form of lockdown on the daily number of positive coronavirus disease 2019 (COVID-19) cases, using interrupted time series analysis. We included the period of March 5 to April 17, 2021, as the period affected by the Friday lockdown, which was applied to seven consecutive Fridays with a total of 168 hours. We used R version 4.0.5 (R Foundation for Statistical Computing, Vienna, Austria) for our analysis. We used Poisson model regression analysis, where the number of positive cases was used as the outcome variable, while the total number of tests, time, and lockdown were used as the predictor variables. We further performed quasi-Poisson regression analysis to confirm the first model. On Poisson model regression analysis, it was found that there was an evidence of an increase in the number of positive COVID-19 cases following the intervention of Friday lockdown, with a p value of <0.001 (relative risk, 1.569; 95% confidence interval, 1.549-1.590). On using quasi-Poisson regression, similar results were found with a wider confidence interval. We concluded that a single weekend day lockdown led to an increase in the number of daily cases of COVID-19. Therefore, we recommend authorities to adhere to evidence-based measures or to the WHO recommendations in the dealing with this pandemic.

Influence of SARS-CoV-2 Variant B.1.1.7, Vaccination, and Public Health Measures on the Spread of SARS-CoV-2

The spread of SARS-CoV-2 and the resulting disease COVID-19 has killed over 2.6 million people as of 18 March 2021. We have used a modified susceptible, infected, recovered (SIR) epidemiological model to predict how the spread of the virus in regions of France will vary depending on the proportions of variants and on the public health strategies adopted, including anti-COVID-19 vaccination. The proportion of SARS-CoV-2 variant B.1.1.7, which was not detected in early January, increased to become 60% of the forms of SARS-CoV-2 circulating in the Toulouse urban area at the beginning of February 2021, but there was no increase in positive nucleic acid tests. Our prediction model indicates that maintaining public health measures and accelerating vaccination are efficient strategies for the sustained control of SARS-CoV-2.