This Week in Infectious Disease — Oct 2, 2026

This AudioScholar briefing is generated by artificial intelligence for healthcare professionals and trainees. It is not medical advice.

Welcome to This Week in Infectious Disease. This week we're covering 10 notable papers spanning vaccine-preventable disease and the fragility of immunisation programmes, mycobacterial infection from pharmacokinetics to trial design, and the fine-tuning of antimicrobial therapy in endocarditis and resistant Gram-negatives. Let's dive in.

We'll start with measles, because two reports in Emerging Infectious Diseases describe what happens when a successful immunisation programme comes apart. Rabbi and colleagues report nationwide surveillance from Bangladesh across roughly two months in 2026, with more than sixty-seven thousand suspected and nearly nine thousand laboratory-confirmed measles cases across all eight administrative divisions, and several hundred deaths among suspected cases [1]. Their reading is that despite high reported coverage, transmission persisted because of residual immunity gaps, with vaccine stockouts, discontinued campaigns and overestimation of coverage as the likely contributors. The companion analysis from Bhuiya and colleagues extends the window to six months and counts more than one hundred and seventy thousand suspected and twenty thousand confirmed cases, with around nine hundred deaths among suspected cases [2]. The children affected were disproportionately unvaccinated or underimmunised, and the authors trace the collapse to political instability during 2024 and 2025, a change in procurement policy, discontent among field staff, COVID-era service disruption and delayed supplementary campaigns, compounded by interrupted vitamin A supplementation and worsening malnutrition that amplified severity. These are surveillance and descriptive data, not causal analyses, but together they make a concrete point for clinicians interpreting coverage statistics anywhere: reported coverage and actual population immunity can diverge sharply, and the authors argue for depoliticised programmes, buffer vaccine stocks and microlevel surveillance rather than reliance on headline coverage figures.

Staying with vaccines, The Lancet Infectious Diseases reports the phase 2b trial of BPZE1, an intranasal live attenuated pertussis vaccine, in children aged six to seventeen who had been primed with acellular vaccines [3]. Faust and colleagues randomised three hundred and sixty-six children across sixteen sites in the United Kingdom, Australia and Costa Rica to intranasal BPZE1 alone, intramuscular Tdap alone, or both. The primary immunogenicity endpoint was met: nasal secretory IgA against whole-cell Bordetella pertussis extract rose roughly three to four fold by day twenty-nine in both BPZE1-containing groups. Importantly for co-administration, serum IgG responses to the acellular pertussis antigens in the combined group were comparable to Tdap alone, and every child in both Tdap groups reached protective diphtheria and tetanus antibody levels. This is an immunogenicity and safety trial, not an efficacy trial, so whether mucosal IgA translates into reduced transmission in children remains the open question, and phase 3 data will be needed before this changes any schedule. Also on the vaccine-preventable front, Open Forum Infectious Diseases reports congenital cytomegalovirus prevalence in rural Uganda, where Davis and colleagues found congenital infection in just under four percent of infants, associated with lower gravidity and with placental malaria, and documented extremely intense early-life transmission, with around ninety-seven percent of children having acquired cytomegalovirus IgG by age three [4]. That prevalence is several-fold higher than typical high-income estimates, and it reframes congenital cytomegalovirus as a major, largely unmeasured contributor to childhood hearing loss and disability in high-seroprevalence settings.

The mycobacterial papers this week run from bedside physiology to trial design. In Open Forum Infectious Diseases, Kurver and colleagues prospectively monitored eighty-one HIV-negative patients admitted with pulmonary tuberculosis at a Dutch referral centre and found that about a quarter of patients developed a paradoxical reaction, defined as new or worsening tachypnoea with hypoxaemia or a new oxygen requirement after excluding alternative causes, at a median of thirteen days into treatment [5]. These reactions were not treatment failures: drug levels were adequate and mycobacterial loads fell in both groups. What distinguished them was inflammation, with higher C-reactive protein, neutrophil counts, neutrophil-to-lymphocyte ratio and ferritin, alongside lower lymphocytes, monocytes, albumin and haemoglobin, and the inflammatory signature was detectable in the weeks before onset. More extensive radiographic involvement and higher baseline bacillary load also tracked with risk. This is a single-centre cohort, so the prediction model is hypothesis-generating, but the authors suggest baseline inflammatory markers could eventually support stratified preemptive immunomodulation. Alongside that, Antimicrobial Agents and Chemotherapy reports intrapulmonary pharmacokinetics in nontuberculous mycobacterial lung disease, where Watanabe and colleagues measured plasma and resected lung drug concentrations in twenty-four patients undergoing surgery in Japan [6]. The lung-to-plasma partitioning spanned an extraordinary range, from essentially no concentration for amikacin whether given intravenously or inhaled, to about five-fold for rifampicin, forty-fold for ethambutol, several hundred-fold for azithromycin, and on the order of tens of thousands-fold for clofazimine, with intrapulmonary half-lives measured in months for the macrolide and years for clofazimine. Critically, drug penetration into cavities and into nodular bronchiectatic lesions was not clearly reduced compared with normal lung tissue, which the authors interpret as meaning lesion phenotype alone has limited value for guiding drug selection. Small, single-centre and surgical, so this informs dosing research rather than current regimens. And in The Lancet Global Health, Ruhwald and colleagues argue in a health policy paper that symptom-triggered case detection in tuberculosis vaccine efficacy trials misses a substantial share of bacteriologically confirmed disease [7]. Using the placebo arm of the M72/AS01E phase 2b trial as a template, they estimate that near point-of-care molecular screening applied regardless of symptoms would detect roughly forty percent more bacteriologically confirmed endpoints. They are explicit that this is an illustrative scenario, not a direct estimate of trial efficiency, and that analytical validation and regulatory alignment would have to come first.

Our last cluster is about sharpening antimicrobial decisions. In Open Forum Infectious Diseases, Bhattarai and colleagues retrospectively reviewed one hundred and thirteen patients across multiple centres who had valve surgery during the acute phase of endocarditis treatment [8]. Just under a third of patients had a positive intraoperative valve culture, and the strongest determinant was simply how long antibiotics had been given beforehand, with each additional preoperative day associated with about a fifteen percent lower odds of a positive culture; median preoperative therapy was around six and a half days in the positive-culture group versus thirteen days in those with negative cultures. Enterococcal endocarditis carried roughly four-fold higher odds of a positive valve culture than streptococcal disease. Relapse was rare, just one case, and it occurred in a patient whose valve culture was negative. Notably, close to two thirds of the patients with negative valve cultures received a median of about eight days of what the authors judged avoidable intravenous therapy. That is retrospective, single-cohort evidence, and it does not establish safety of shorter courses, but it does reopen the question of postoperative duration after surgical source control. From the International Journal of Antimicrobial Agents, Baek and colleagues sequenced thirteen KPC-2-producing Klebsiella pneumoniae isolates that were non-susceptible to new beta-lactam inhibitor combinations, overwhelmingly imipenem-relebactam, despite predating those drugs' clinical use [9]. The mechanism was porin loss rather than enzyme: truncating ompK36 mutations in about six in ten isolates, non-truncating variants in others, with reduced ompK36 expression, while KPC-2 expression barely varied. Raising the relebactam concentration restored activity in all but one isolate, which had lost both major porins. This is in vitro mechanistic work, but it explains resistance that genotype-based KPC reporting would miss.

Finally, Turner and colleagues, also in Open Forum Infectious Diseases, revisited livestock as a source of community-acquired Clostridioides difficile using more than twenty-six thousand tests from a North Carolina health system plus environmental sampling [10]. Living in the same watershed as commercial swine operations was associated with a small increase in risk, about eleven percent higher odds, after adjustment for age, comorbidity, antibiotics and healthcare contact, and that association sat right at the edge of statistical significance. Clostridioides difficile gene targets were ubiquitous in municipal wastewater but undetectable in the three regional surface waters sampled, so the proposed waterborne pathway was not confirmed.

If you only have time for one paper this week, make it the endocarditis valve culture study in Open Forum Infectious Diseases [8]. It reopens a question most of us answer by habit, which is how much postoperative intravenous therapy a patient actually needs once the infected valve is out and the tissue culture is sterile.

Here is what this week's evidence adds up to in Infectious Disease. First, two Bangladesh surveillance reports show that reported immunisation coverage can badly overstate population immunity, and that procurement and political disruption translate into tens of thousands of measles cases within months. Second, intranasal BPZE1 met its mucosal immunogenicity endpoint in acellular-primed children without blunting Tdap serology, which is encouraging but still pre-efficacy. Third, in tuberculosis, paradoxical reactions in HIV-negative patients appear to be preceded by a measurable systemic inflammatory signature rather than by treatment failure, and in nontuberculous mycobacterial disease lesion type does not appear to be the barrier to drug penetration that has often been assumed, though both datasets are small and single-centre. Fourth, retrospective endocarditis data suggest positive valve cultures are driven largely by short preoperative antibiotic exposure and do not predict relapse, which supports but does not prove a case for shorter postoperative courses. And fifth, resistance to imipenem-relebactam in KPC-2 Klebsiella can arise from porin loss alone, which is dose-dependently reversible in vitro and invisible to carbapenemase genotyping.

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.

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