Complexity of the Basic Reproduction Number (R0).

The basic reproduction number (R0), also called the basic reproduction ratio or rate or the basic reproductive rate, is an epidemiologic metric used to describe the contagiousness or transmissibility of infectious agents. R0 is affected by numerous biological, sociobehavioral, and environmental factors that govern pathogen transmission and, therefore, is usually estimated with various types of complex mathematical models, which make R0 easily misrepresented, misinterpreted, and misapplied. R0 is not a biological constant for a pathogen, a rate over time, or a measure of disease severity, and R0 cannot be modified through vaccination campaigns. R0 is rarely measured directly, and modeled R0 values are dependent on model structures and assumptions. Some R0 values reported in the scientific literature are likely obsolete. R0 must be estimated, reported, and applied with great caution because this basic metric is far from simple.

Vaccination Coverage for Selected Vaccines, Exemption Rates, and Provisional Enrollment Among Children in Kindergarten - United States, 2016-17 School Year.

State and local school vaccination requirements help protect students and communities against vaccine-preventable diseases (1). CDC reports vaccination coverage and exemption data for children attending kindergarten (kindergartners) collected by federally funded immunization programs in the United States.* The typical age range for kindergartners is 4-6 years. Although vaccination requirements vary by state (the District of Columbia [DC] is counted as a state in this report.), the Advisory Committee on Immunization Practices recommends that children in this age range have received, among other vaccinations, 5 doses of diphtheria, tetanus, and acellular pertussis vaccine (DTaP), 2 doses of measles, mumps, and rubella vaccine (MMR), and 2 doses of varicella vaccine (2). This report summarizes 2016-17 school year MMR, DTaP, and varicella vaccination coverage reported by immunization programs in 49 states, exemptions in 50 states, and kindergartners provisionally enrolled or within a grace period in 27 states. Median vaccination coverage† was 94.5% for the state-required number of doses of DTaP; 94.0% for 2 doses of MMR; and 93.8% for 2 doses of varicella vaccine. The median percentage of kindergartners with an exemption from at least one vaccine§ was 2.0%, similar to 2015-16 (1.9%). Median grace period and provisional enrollment was 2.0%. Vaccination coverage remains consistently high and exemptions low at state and national levels. Local-level vaccination coverage data provide opportunities for immunization programs to identify schools, districts, counties, or regions susceptible to vaccine-preventable diseases and for schools to address undervaccination through implementation of existing state and local vaccination policies (1) to protect communities through increased coverage.

Prevalence of Sports Injuries Among 13- to 15-Year-Old Students in 25 Low- and Middle-Income Countries.

The goal of this study was to compare the sex-specific prevalence rate of serious sports injuries in the past year among students ages 13-15 years from 25 low- and middle-income countries (LMICs) globally. Data from 46,922 nationally-representative students who participated in the Global School-based Student Health Survey (GSHS) were analyzed using complex samples analysis. The GSHS defines injuries as serious when they cause at least one full day of missed school or usual activities or require clinical treatment. Students reporting more than one serious injury in the past year are asked about the single most serious injury. The proportion of students reporting at least one serious injury in the past year ranged from 15-71 % (median 44 %) among boys and 8-70 % (median 30 %) among girls. The proportion of most-serious injuries in the past year that were sports-related ranged from 25-60 % among injured boys (median 35 %) and 12-56 % among injured girls (median 24 %). The most common types of sports-related injuries were broken bones and dislocated joints, reported by 13-62 % (median 28 %) of boys with sports injuries and 10-86 % (median 25 %) of girls with sports injuries. Although the annual injury rates among early adolescents vary widely between countries, the GSHS shows that sports injuries are common globally among both male and female middle school students. Understanding global trends in the health risks for various population groups, such as adolescents, allows community health partnerships to proactively address health needs in the communities they serve.

Variation in Vaccination Data Available at School Entry Across the United States.

OBJECTIVES: To compile substate-level data on US school-age children's vaccination rates. METHODS: For states that did not have suitable data online, in 2015 we submitted information requests to the state health department and followed up with the state's Freedom of Information Act when necessary. RESULTS: The accessibility, scale, and types of vaccination data varied considerably. Whereas 26 states provided data online, 14 released data only after a Freedom of Information Act request. School or school-district data were available for 24 states, 19 at the county level, 2 at the health department level, and 6 provided no substate-level data. CONCLUSIONS: Effective vaccination policy requires a robust understanding of vaccination behavior. Some states make it difficult to access data or provide low-resolution data of limited value for identifying vaccination behavior.

Injury incidence among middle school students aged 13-15†years in 47 low-income and middle-income countries.

A total of 95 811 students aged 13-15 years participated in nationally representative Global School-based Student Health Surveys (GSHS) in 47 low-income and middle-income countries conducted between 2003 and 2012. On average, about 40% of the participants in each country reported at least one injury in the past year that was serious enough to cause the student to miss at least one full day of usual activities (such as school, sports and a job) or to require treatment by a healthcare professional. In 40 of the 47 countries, boys reported a significantly higher injury rate than girls. Based on these numbers, injuries likely cause approximately four million days of school absence by lower secondary school students annually. Most of these injuries are preventable.