typhoid conjugate vaccine

A Carriage-Structured Model of Meningococcal Meningitis: Backward Bifurcation, Seasonal Recurrence, and the Reach of Conjugate-Vaccine Strategies in the African Meningitis Belt.

Gatyeni Siphokazi Princess SP

Epidemic meningococcal meningitis in the African meningitis belt recurs on two timescales: a sharp annual dry-season peak and irregular multi-annual epidemics five to twelve years apart, whose mechanistic origin remains unsettled. Invasive disease is a rare, dead-end outcome of asymptomatic nasopharyngeal carriage, so susceptible-infectious templates misrepresent community transmission. We ask how carriage structure shapes bifurcation, seasonal recurrence, and the reach of conjugate-vaccine strategies. We formulate a deterministic carriage-structured model in which only carriers transmit, immunity against re-acquisition is leaky, and a conjugate vaccine is imperfect and wanes. We use the Castillo-Chavez-Song centre manifold method, numerical continuation, Floquet and eigenvalue analysis, and scenario simulations of abstract rate- and pulse-type interventions parameterised from published belt ranges. The basic reproduction number R0 is a property of carriage transmission, decoupled to first order from disease incidence. Backward bifurcation at R0=1 is governed by a threshold ε∗ on carriage-blocking immunity; only the untreated fatality hazard and treatment capacity are absent from the local condition. It is impossible without vaccination and, with any positive routine coverage, persists across the plausible coverage range, giving vaccine-induced bistability. Continuation confirms a fold at R0,c≈0.946 (φ=0.12yr-1, weak carriage immunity), but not at baseline immunity. Under seasonal forcing, dynamics converge to a simple annual cycle throughout the region searched; we found no multi-annual recurrence, although damped eigenmodes of the unforced system have periods overlapping the observed interval. Within this deterministic, single-strain model, irregular recurrence likely requires additional structure, with stochastic amplification of damped cycles a natural next step. Whether sustained immunisation eliminates epidemics or merely postpones them may depend on the same carriage-efficacy threshold that governs the bistability result.

Azithromycin versus ceftriaxone for uncomplicated typhoid fever in children: a systematic review and meta-analysis of randomized controlled trials.

Manzoor Muhammad Umair MU, Anwar Aqsa A, Owais Muhammad M, Umar Syed S et al.

Typhoid fever caused by Salmonella enterica serovar Typhi remains a major cause of febrile illness among children in low- and middle-income countries, particularly in South and Southeast Asia. The increasing emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains has substantially limited available treatment options and highlighted the need for effective oral therapies. Azithromycin and ceftriaxone are commonly used for uncomplicated typhoid fever in children; however, evidence comparing their efficacy and safety remains limited. To compare the efficacy and safety of azithromycin versus ceftriaxone for the treatment of uncomplicated typhoid fever in children through a systematic review and meta-analysis of randomized controlled trials. A comprehensive literature search was conducted in PubMed, the Cochrane Library, ClinicalTrials.gov, Google Scholar, and WHO ICTRP from inception to April 2026 in accordance with PRISMA 2020 guidelines. Randomized controlled trials comparing azithromycin with ceftriaxone in children under 18 years of age with uncomplicated typhoid fever were included. The primary outcome was the clinical cure rate. Secondary outcomes included fever clearance time, microbiological cure, relapse, and adverse events. Data extraction and risk of bias assessment using the Cochrane Risk of Bias 2 tool were performed independently by two reviewers. Meta-analysis was conducted using a random-effects model, and heterogeneity was assessed using the I² statistic. Six randomized controlled trials involving 492 children (azithromycin = 244; ceftriaxone = 248) were included. All studies were open-label trials conducted in Egypt, India, Pakistan, and Bangladesh. Overall risk of bias was judged to be of some concern, mainly due to the open-label study design. Meta-analysis showed no significant difference between azithromycin and ceftriaxone in clinical cure rate (RR = 0.98, 95% CI 0.93-1.03; P = 0.43) or fever clearance time. Similarly, microbiological cure and adverse event profiles were similar across groups but could not be formally pooled due to heterogeneous reporting. However, azithromycin was associated with fewer relapses than ceftriaxone, though this finding should be interpreted with caution given the low certainty of the evidence. The certainty of evidence was very low for fever clearance and low for the relapse rate. Heterogeneity varied across outcomes, with the highest for fever clearance time. Azithromycin appears to have comparable efficacy and safety to ceftriaxone for the treatment of uncomplicated typhoid fever in children, with a trend toward fewer relapses that warrants cautious interpretation. Its oral administration may provide a practical alternative to parenteral ceftriaxone in endemic settings. Further large-scale randomized trials with standardized outcome reporting are needed to strengthen the current evidence base. Not applicable. PROSPERO Protocol Number: CRD420261383999. LINK: https://www.crd.york.ac.uk/PROSPERO/view/CRD420261383999 .

First mRNA Cancer Vaccine Succeeds in Phase III Trial.

Adding the mRNA-based individualized neoantigen vaccine intismeran autogene to the PD-1 inhibitor pembrolizumab following surgery for melanoma reduced the risk of disease recurrence or death by 42%, according to the results of the phase III INTerpath-0001 trial. The data were presented at the ESMO Congress 2026, held October 23-27, in Madrid, Spain.

Innovative vaccine strategies for sustainable control and eradication of peste des petits ruminants virus.

Bello Muhammad Bashir MB, Hameed Sodiq A SA, Abdullahi Adama Musa AM, Lawal Nafi'u N et al.