Influence of anti-coronavirus disease 2019 policies on 10 pediatric infectious diseases.

BACKGROUND: To combat the coronavirus disease 2019 pandemic, many countries, including Japan, implemented policies limiting social activities and encouraging preventive behaviors. This study examines the influence of such policies on the trends of 10 infectious pediatric diseases: pharyngoconjunctival fever; group A streptococcal pharyngitis; infectious gastroenteritis; chickenpox; erythema infectiosum; hand, foot, and mouth disease; herpangina; respiratory syncytial virus; exanthem subitum; and mumps. METHODS: The research adopted a retrospective cohort study design. We collected data from Japan's National Epidemiological Surveillance Program detailing the incidences of the 10 diseases per pediatric sentinel site for a period beginning at 9 weeks before government-ordered school closures and ending at 9 weeks after the end of the state of emergency. We obtained corresponding data for the equivalent weeks in 2015-2019. We estimated the influence of the policies using a difference-in-differences regression model. RESULTS: For seven diseases (pharyngoconjunctival fever; group A streptococcal pharyngitis; infectious gastroenteritis; chickenpox; erythema infectiosum; hand, foot, and mouth disease; and herpangina), the incidence in 2020 decreased significantly during and after the school closures. Sensitivity analysis, in which the focus area was limited to the policy-implementation period or existing trend patterns, replicated these significant decreases for one of the above mentioned seven diseases - infectious gastroenteritis. CONCLUSIONS: Policies such as school closures and encouragement of preventive behaviors were associated with significant decreases in the incidences of most of the 10 diseases, which sensitivity analysis replicated in infectious gastroenteritis. To determine the long-term effects of these policies, prospective cohort studies are needed.

Effectiveness of case isolation and class suspension in mitigation of enterovirus transmission in children.

BACKGROUND: Appropriate mitigation strategy to minimize enterovirus (EV) transmission among children is essential to control severe EV epidemics. Scientific evidence for the effectiveness of case isolation and class suspension is lacking. METHODS: EV-infected children ≤ eight years are asked to stay at home for seven days. Classes were suspended for seven days if there are more than two classmates having an onset of herpangina or hand, foot, and mouth disease in one classroom within one week. Study subjects are divided into two groups, group A with class suspension for one week and group B without class suspension. RESULTS: Among 4153 reported EV-infected children from 1085 classes in May and June, 2015 were enrolled. Median incidence of EV infection in a class was 7% (range 3% -60%). The incidence was higher in group A (median 14%, range 3-60%) than that in group B (median 6%, range 3-80%) (P < 0.01). The median incidence is highest in day care center (20%), followed by kindergarten (8%), and primary school (4%) (P < 0.01). Most secondary cases in group A appeared within seven days after the disease onset of index case in the same class. The incidence of EV infection remained low and was similar between the two groups eight days and beyond after the disease onset of index cases. CONCLUSIONS: Targeted class suspension for seven days with case isolation for seven days is an effective measure to mitigate transmission of EV infection in children.

Predicting Hand, Foot, and Mouth Disease in Japan Using Google Trends: Infodemiology Study (preprint)

Objectives: We aimed to predict the number of hand, foot, and mouth disease (HFMD) infections before and during the COVID-19 pandemic using Internet search data. Methods: We obtained actual HFMD cases from the National Institute of Infectious Disease and Internet search data using Google Trends between 2004 and 2021 in Japan. We calculated the Pearson correlation coefficients between actual HFMD cases and the search topic "HFMD" from 2004 to 2021. We conducted a cross-correlation analysis between the actual HFMD cases and 43 HFMD-related search terms before and during the pandemic. We identified the most significant predictors of HFMD infection using stepwise multiple linear regression. Results: We found that actual HFMD cases and Internet search volume peaked around July in most years, except for 2020 and 2021. The search topic "HFMD" presented a strong correlation with actual HFMD cases, but the correlation was weaker in 2004, 2008, and 2020. Results from stepwise multiple linear regression exhibited that the search terms "infect," "daycare," "vomit," "HFMD," "eczema," "pain," and "high fever were the most significant predictors before the pandemic, while "infect," "enterovirus," "herpangina," "kindergarten," "myocarditis," "HFMD," "contact infection," "blister," "high fever" "dermatology," and "plantar" were the most significant predictors during the pandemic. Conclusions: The predictors for HFMD infections before and during the COVID-19 pandemic were different. The awareness of HFMD infection in Japan may improved during the COVID-19 pandemic. Continuous monitoring is important to promote public health and prevent resurgence. Public interest reflected in information-seeking behavior can be helpful for public health surveillance.