This Week in Infectious Disease — May 14, 2026

Welcome to This Week in Infectious Disease. This week we're covering 8 notable papers spanning global health prevention, neonatal sepsis, and the evolving landscape of viral infections. Let's dive in.

Our first theme is rethinking prevention strategies in global health, with new data on tuberculosis, malaria, and schistosomiasis.

Two papers this week offer fresh perspectives on curbing tuberculosis. First, a modeling study in The Lancet Global Health provides a powerful reminder of the link between nutrition and TB [7]. Investigators estimated the global impact of eliminating undernutrition on adult tuberculosis incidence. They found that eliminating all undernutrition—defined as a BMI below 18.5—could avert 2.3 million tuberculosis episodes globally. This represents a potential reduction of nearly 24% in global adult incidence, an effect about two-and-a-half times higher than previous estimates. The largest benefits would be seen in the WHO African, South-East Asia, and Eastern Mediterranean regions. This study makes a strong case for scaling up nutritional interventions as a core part of TB control.

Complementing this population-level view, a Personal View in The Lancet Infectious Diseases argues for a more targeted approach to interrupting transmission [1]. The authors review historical and contemporary data on Mycobacterium tuberculosis superspreading—the fact that a small number of individuals are responsible for the majority of secondary infections. They argue that this isn't just a curious feature of TB epidemiology, but a strategic opportunity. By focusing interventions on identifying and managing superspreaders, we could have an outsized impact on transmission, disrupting the cycle more effectively than with current strategies alone.

From TB, we turn to malaria. In a landmark paper published in The Lancet, we now have mortality data from the rollout of the RTS,S malaria vaccine [8]. This was an observational evaluation of the cluster-randomized implementation program in Ghana, Kenya, and Malawi over 4 years. The program involved routine delivery of a four-dose schedule to young children.

Results

The key finding is a significant reduction in all-cause mortality, excluding injuries. In children eligible for the vaccine, its introduction was associated with a 13% lower mortality rate compared to areas without the vaccine. This means the vaccine averted about one in every eight deaths in this age group. This impact was achieved despite relatively low uptake of the fourth dose, which was only about 40%, although coverage for the first three doses was higher, around 71% for dose three. These results provide powerful, real-world evidence of the vaccine's life-saving impact and add urgency to its wider deployment across sub-Saharan Africa.

Finally in this section, a review in The Lancet Global Health shines a light on the neglected burden of schistosomiasis in women and adolescent girls [3]. The authors focus on female genital schistosomiasis, or FGS, caused by Schistosoma haematobium eggs depositing in genital tissue. This condition affects over 40 million women and girls, causing pain, discharge, menstrual problems, and subfertility, often mistaken for sexually transmitted infections. The review argues that health systems in endemic areas are poorly equipped to diagnose and treat FGS, and that women are often excluded from schistosomiasis control strategies. The authors call for multifaceted approaches that specifically target this devastating condition.

Our second theme this week focuses on neonatal sepsis, with two papers that together paint a detailed and alarming picture of the problem in low- and middle-income countries.

First, the CHAMPS study, published in The Lancet Infectious Diseases, sought to determine the specific causes of neonatal death across seven sites in Africa and South Asia [2]. Using minimally invasive post-mortem tissue sampling, the investigators were able to conduct detailed pathogen testing.

Results

Infections were implicated in the causal pathway for 44% of the 2,609 neonatal deaths studied. The dominant pathogens were Gram-negative bacteria, which were responsible for nearly three-quarters of infection-related deaths. The single most common pathogen was Klebsiella pneumoniae, found in over 40% of infection-related deaths, followed by Acinetobacter baumannii and E. coli. The authors conclude that the current empirical antibiotic regimens for neonatal sepsis in these settings may need review, and that over 80% of these deaths could have been averted with better facility-based care.

Building directly on this finding, a study in PLoS Medicine investigated the role of nosocomial transmission in Klebsiella pneumoniae neonatal sepsis [5]. Using whole-genome sequencing on over 1,500 isolates from 27 neonatal units in 13 African and South Asian countries, researchers inferred transmission clusters based on genetic and temporal proximity.

Results

The findings are stark. An estimated 68% of all neonatal K. pneumoniae infections were part of a nosocomial transmission cluster. Even after excluding the first case in each cluster, the data suggest that at least 58% of infections were acquired via hospital-based transmission. The risk of being in a transmission cluster was significantly higher for isolates carrying ESBL or carbapenemase genes. Together, these two studies show that not only is K. pneumoniae a leading cause of neonatal death, but that a substantial majority of these infections are spreading within the very neonatal units meant to provide care, highlighting an urgent crisis in infection prevention and control.

Our final theme covers new developments in viral infections, with a new tool for prophylaxis and a newly identified long-term risk.

First, in The New England Journal of Medicine, we have a randomized, placebo-controlled trial of ensitrelvir for COVID-19 post-exposure prophylaxis [4]. The study enrolled household contacts of patients with COVID-19 who were themselves negative at baseline. They were randomized to receive a five-day course of oral ensitrelvir or placebo within 72 hours of the index patient's symptom onset.

Primary Outcome

The primary endpoint was the development of symptomatic, lab-confirmed COVID-19. The incidence was 2.9% in the ensitrelvir group versus 9.0% in the placebo group. This translates to a risk ratio of 0.33, meaning ensitrelvir reduced the risk of getting sick by about two-thirds. Adverse events were similar between the groups, with no safety concerns. This study establishes ensitrelvir as an effective option for post-exposure prophylaxis in this setting.

Finally, a study in Cell raises a concerning possibility about the long-term consequences of severe viral pneumonia [9]. Investigators explored the link between severe respiratory viral infections, including COVID-19, and subsequent lung cancer development. Using data from patients previously hospitalized with severe COVID-19, they found an increased risk of subsequent lung cancer. They then used multiple mouse models to probe the mechanism.

Mechanism

They found that a prior severe viral infection reprogrammed the lung into a pro-tumor microenvironment. This was characterized by a sustained accumulation of tumor-associated neutrophils and heightened immunosuppression, effectively creating fertile ground for cancer growth. The researchers observed persistent inflammatory memory in immune and structural cells. Importantly, vaccination helped mitigate this infection-enhanced tumor progression in the animal models. This work establishes a causal link and suggests a need for enhanced lung cancer surveillance in patients who have recovered from severe viral pneumonia.

If you only have time for one paper this week, make it the evaluation of the RTS,S malaria vaccine in The Lancet [8]. It provides the real-world, all-cause mortality data that confirms the profound public health impact of this new vaccine, validating years of research and providing the critical evidence needed to accelerate its deployment to save children's lives.

Here are the key takeaways from this week in Infectious Disease.

First, the RTS,S malaria vaccine reduces all-cause mortality in eligible children by about 13% in routine program settings, making accelerated deployment a global health priority.

Second, in low- and middle-income countries, a majority of neonatal sepsis cases caused by Klebsiella pneumoniae are due to nosocomial transmission. This is a crisis that demands an immediate and massive focus on infection prevention and control in neonatal units.

Third, for post-exposure prophylaxis against COVID-19, a 5-day course of oral ensitrelvir is an effective option for household contacts when started within 72 hours of exposure.

Fourth, severe viral pneumonia, including from COVID-19, can create a pro-tumorigenic environment in the lungs. This may warrant considering enhanced lung cancer surveillance for patients with a history of severe respiratory viral infection.

Finally, don't underestimate the basics. Eliminating undernutrition could be one of our most powerful tools against tuberculosis, potentially averting nearly a quarter of adult cases globally.

That's your roundup for This Week in Infectious Disease. The full transcript and references are available on the episode page in your AudioScholar library. This is an AI-curated summary — for clinical decisions, always consult primary sources and current guidelines. See you next week.

This is an automated summary generated by artificial intelligence, which can make mistakes. Always review the original source materials.