Cases of influenza-like illness (ILI) among students in a Wisconsin school district dropped by nearly half after winter and spring breaks, with the largest dips occurring when the breaks coincided with spikes in local flu activity, University of Wisconsin researchers report.

Published yesterday in Influenza and Other Respiratory Viruses, the observational study compared school absenteeism for ILI (a-ILI) among about 4,100 K-12 students in the 2 weeks before and after winter and spring breaks from September 2014 to June 2019. The investigators inserted a 9-day "pseudobreak" 5 weeks before spring break when school was in session as the control.

"School-aged children and school reopening dates have important roles in community influenza transmission," the authors wrote. "Children frequently have larger social networks, experience prolonged viral shedding, have lower coverage rates for influenza vaccine, and may lack sufficient preexisting immunity for herd effects.^"

More flu among younger students

The average numbers of flu cases during the 2 weeks before winter and spring breaks were 130.4 (range, 51 to 262) and 151.4 (range, 69 to 275), respectively. The average case counts for the periods after winter and spring breaks were 82 (range, 33 to 152) and 49.6 (range, 33 to 74), respectively. Greater flu activity was reported among younger students than among those in middle and high schools.

The 2 weeks after breaks were tied to a statistically significant decline in the likelihood of flu, as well as after winter (estimated odds ratio [OR], 0.68) and spring (OR, 0.33) breaks.

These findings suggest that brief breaks of in-person schooling, such as planned breaks lasting 9–16 calendar days, can effectively reduce influenza in schools and community spread.

The 2 weeks before and after pseudobreaks saw average flu tallies of 106 (range, 43 to 200) and 100.8 (range, 71 to 131), respectively. No significant differences were seen in the 2 weeks before and after pseudobreaks.

"These findings suggest that brief breaks of in-person schooling, such as planned breaks lasting 9–16 calendar days, can effectively reduce influenza in schools and community spread," the researchers wrote. "Additional analyses investigating the impact of well-timed shorter breaks on a-ILI may determine an optimal duration for brief school closures to effectively suppress community transmission of influenza."

A new preprint study published on the preprint server medRxiv estimates how many lives were directly saved by vaccinating adults against COVID-19 in Europe from December 2020 through March 2023. Overall, the authors said the vaccines reduced deaths by 57% and saved an estimated 1.4 million lives in Europe.

As of March 2023, the 34 countries and territories in the World Health Organization’s European region had reported 2.2 million cases. The authors of the study estimated the impact of COVID-19 vaccination in adults by age-group, vaccine dose, and period of circulation of variants of concern.

Among adults over 25 years, 1.5 million lives (range, 0.7 to 2.6 million) were saved because of vaccines during the first 2.5 years of use. Overall, the first booster dose of vaccine delivered before the Omicron variant became dominant saved the most lives, 721,122 of 1,408,967 (57%) of all lives saved. The first booster dose became available in Europe in July 2021.

67% of lives saved during Omicron period

Most lives (67%) were saved during the Omicron period (942,571), and lives saved were almost all among adults ages 60 and older (96%, or 1,349,617).

Booster doses in older age-groups played an important role in saving lives.

The researchers previously estimated that vaccination directly saved 469,186 lives among people 60 years and older in 33 European countries during first year of the vaccination program.

"Booster doses in older age-groups played an important role in saving lives: early introduction of the first booster dose, which was recommended because of concerns about waning protection against severe disease," the authors said. "The first booster dose was responsible for the majority of lives saved, highlighting the importance of up-to-date vaccination in this high-risk age group."

A study of six US cities found a high prevalence of bacterial sexually transmitted infections (STIs) in transgender women (TGW), particularly those with HIV, researchers reported today in the Journal of Infectious Diseases.

Using baseline data from the Leading Innovation for Transgender Women's Health and Empowerment study, which examined HIV incidence and other health outcomes in TGW in six southeastern and eastern US cities (Atlanta, Baltimore, Boston, Miami, New York, and Washington, DC), a team led by researchers from Johns Hopkins Bloomberg School of Public Health analyzed bacterial STI test results from 1,018 participants. The primary outcome was the prevalence of at least one bacterial STI (gonorrhea, chlamydia, or syphilis) at any anatomic site.

Prevalence higher in those with HIV

The median age of participants was 29 years, 29% were Black, 27% were Hispanic, and 27% had HIV. The overall prevalence of any bacterial STI was 16% but was threefold higher in TGW with HIV (32% vs 11% among those without HIV). After adjustments for age, race and ethnicity, and region, HIV infection remained significantly associated with any bacterial STI (adjusted prevalence ratio, 1.9; 95% confidence interval, 1.39 to 2.62).

Among TGW without HIV, bacterial STI prevalence differed by geographic region, race and ethnicity, and gender identity, and was positively associated with reporting more than 1 sexual partner, hazardous alcohol use, homelessness, having safety concerns regarding transit to healthcare, and no prior receipt of gender-affirming health services. Among TGW with HIV, older age was inversely associated with bacterial STI.

...the variation in bacterial STI prevalence and correlates seen between TGW with and without HIV highlights the differential burden and needs of these two populations

The study authors say the findings underscore the need to develop interventions that are tailored to the unique needs and risks of each population.

"Although participants with and without HIV had a high prevalence of bacterial STIs, the variation in bacterial STI prevalence and correlates seen between TGW with and without HIV highlights the differential burden and needs of these two populations," they wrote. "Elucidating the ways in which situated vulnerabilities are associated with STI risk may help inform more tailored intervention strategies for each population."

Mpox cases continue to be reported at a low level in the European region, with 138 cases from 11 countries and areas reported over the last month, according to a joint update from the European Centre for Disease Prevention and Control (ECDC) and the World Health Organization (WHO) European regional office.

The groups are now posting the updates quarterly rather than monthly, noting that since their last report in October, the region has reported 472 cases from 19 cases and areas.

Countries reporting the most cases are still Spain, Portugal, the United Kingdom, and Germany.

Of mpox samples that were sequenced, all belonged to clade 2, known as the West African clade. Clade 2 is fueling the global outbreak in countries outside of Africa, which mainly involves men who have sex with men. Meanwhile, clade 1—known to be more virulent and deadly—is still spreading in Africa, where the virus was recently linked to a large outbreak in the Democratic Republic of Congo (DRC), the country's first involving sexual transmission of the virus.

• The Philadelphia Department of Public Health yesterday reported another confirmed measles case in the city's outbreak, raising the total to nine. The latest illness involves a fifth case related to exposures at a daycare facility. The outbreak began in December, with illnesses reported at a hospital, then a cluster in children at a daycare. The cluster at the daycare occurred after a sick patient attended the facility despite quarantine and exclusion instructions. City health officials are tracking potential exposures and are offering measles, mumps, and rubella (MMR) vaccination at multiple community sites.
• The US Senate Health, Education, Labor, and Pensions (HELP) committee announced yesterday that it will hold a full committee hearing at 9:00 am (EST) tomorrow on addressing long COVID, focusing on advancing research and improving patient care. In a statement, Sen. Bernie Sanders, (I.-Vt.) said that the impact of the pandemic is still felt by millions of families. "Lives are at stake. I look forward to hearing from patients, experts, and researchers about what we must do to address this crisis, including the advanced research and patient care that so many Americans desperately need," he said. The committee will hear testimony from two panels, one a group of long-COVID patients and the other comprising medical doctors and researchers.
• Brazil's health ministry this week announced some initial details about a plan to launch the dengue vaccine through its public system, which will make it the first country in the world to do so. The ministry incorporated the Qdenga vaccine, made by Takeda, in December and said the company expects to deliver 5.2 million doses between February and November. The company has donated another 12 million doses. Officials said doses will be staggered throughout the year, based on the company's vaccine delivery schedule, with a goal of vaccinating about 3.2 million people with the two-dose schedule. Technical experts advised the ministry that doses be prioritized to children ages 6 to 16 years old, based on World Health Organization recommendations. The Americas region reported record dengue cases in 2023, with Brazil as the hardest hit country.