Typhoid remains a major cause of illness and death globally. In this trial, the efficacy of a typhoid conjugate vaccine was assessed in children in Nepal. A total of 20,019 children were randomly ...assigned to receive either a TCV or a meningococcal A vaccine. The TCV was associated with a decrease of 81.6% in
Salmonella
Typhi bacteremia.
Abstract
Influenza vaccines have a long history of safety and demonstrated efficacy; however, they are seldom used in low- and middle-income countries (LMICs). Although reasons for underuse are ...multifactorial and differ from country to country, the need for up to twice-annual reformulation and yearly vaccination are obstacles to influenza prevention in LMICs. Major efforts are underway to produce next-generation influenza vaccines that provide durable protection against drifted strains, and such vaccines could address these unmet needs. However, additional information is required to influence immunization policies in most LMICs. Better estimates of vaccine impact on important public health outcomes, more affordable vaccines, improved programmatic suitability, and strengthened immunization delivery infrastructures are needed and must be considered early during the development of new vaccines if widespread adoption in LMICs is to be achieved.
Abstract
The disease burden of typhoid fever remains high in endemic areas in Asia and Africa, especially in children. Recent clinical trials conducted by the Typhoid Vaccine Acceleration Consortium ...show typhoid conjugate vaccine (TCV) to be safe, immunogenic, and efficacious at preventing blood culture-confirmed typhoid fever in African and Asian children. Pakistan, Liberia, and Zimbabwe recently introduced TCV through campaigns and routine childhood immunizations, providing protection for this vulnerable population. It is essential to continue this momentum while simultaneously filling data gaps—including typhoid complications—to inform decision-making on TCV introduction. A multidisciplinary approach including surveillance, water, sanitation, and hygiene investments, and large-scale TCV introduction is needed to decrease the burden and mortality of typhoid fever.
NVX-CoV2373 is a vaccine containing a full-length stabilized recombinant spike protein trimer that is administered in two doses 3 weeks apart along with a saponin-based adjuvant. In a randomized ...trial, approximately 20,000 participants received the vaccine and 10,000 a placebo. Vaccine efficacy against infection was 90%, and reactogenicity was similar to that of other Covid-19 vaccines.
Abstract
Coronavirus disease 2019 (COVID-19) vaccine trials provide valuable insight into the safety and efficacy of vaccines, with individually randomized, placebo-controlled trials being the gold ...standard in trial design. However, a myriad of variables must be considered as clinical trial data are interpreted and used to guide policy decisions. These variables include factors such as the characteristics of the study population and circulating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strains, the force of infection, the definition and ascertainment of endpoints, the timing of vaccine efficacy assessment, and the potential for performance bias. In this Viewpoints article, we discuss critical variables to consider when comparing efficacy measurements across current and future COVID-19 vaccine trials.
COVID-19 vaccine trials provide valuable insight into the safety and efficacy of vaccines. Simple comparison of trial efficacy estimates, however, is problematic. When comparing efficacy results from COVID-19 vaccine trials, factors related to trial context and design must be considered.
Typhoid fever is responsible for a substantial health burden in low- and middle-income countries (LMICs). New means of prevention became available with the prequalification of typhoid conjugate ...vaccines (TCV) by the World Health Organization (WHO) in 2018. Policymakers require evidence to inform decisions about TCV. The economic burden related to typhoid fever can be considerable, both for healthcare providers and households, and should be accounted for in the decision-making process. We aimed to understand the breadth of the evidence on the cost of typhoid fever by undertaking a scoping review of the published literature. We searched scientific databases with terms referring to typhoid fever cost of illness to identify published studies for the period January 1st 2000 to May 24.sup.th 2024. We also conferred with stakeholders engaged in typhoid research to identify studies pending completion or publication. We identified 13 published studies reporting empirical data for 11 countries, most of them located in Asia. The total cost of a typhoid episode ranged from $23 in India to $884 in Indonesia (current 2022 United States Dollar USD). Household expenditures related to typhoid fever were characterized as catastrophic in 9 studies. We identified 5 studies pending completion or publication, which will provide evidence for 9 countries, most of them located in Africa. Alignment in study characteristics and methods would increase the usefulness of the evidence generated and facilitate cross-country and regional comparison. The gap in evidence across regions should be mitigated when studies undertaken in African countries are published. There remains a lack of evidence on the cost to treat typhoid in the context of increasing antimicrobial resistance. Decision-makers should consider the available evidence on the economic burden of typhoid, particularly as risk factors related to antimicrobial resistance and climate change increase typhoid risk. Additional studies should address typhoid illness costs, using standardized methods and accounting for the costs of antimicrobial resistance.
Rotavirus vaccines are now globally recommended by the World Health Organization (WHO), but in early 2009 WHO's Strategic Advisory Group of Experts on Immunization reviewed available data and ...concluded that there was no evidence for the efficacy or effectiveness of a two-dose schedule of the human rotavirus vaccine (HRV; Rotarix) given early at 6 and 10 wk of age. Additionally, the effectiveness of programmatic rotavirus vaccination, including possible indirect effects, has not been assessed in low-resource populations in Asia.
In Bangladesh, we cluster-randomized (1:1) 142 villages of the Matlab Health and Demographic Surveillance System to include two doses of HRV with the standard infant vaccines at 6 and 10 wk of age or to provide standard infant vaccines without HRV. The study was initiated November 1, 2008, and surveillance was conducted concurrently at Matlab Diarrhoea Hospital and two community treatment centers to identify children less than 2 y of age presenting with acute rotavirus diarrhea (ARD) through March 31, 2011. Laboratory confirmation was made by enzyme immunoassay detection of rotavirus antigen in stool specimens. Overall effectiveness of the HRV vaccination program (primary objective) was measured by comparing the incidence rate of ARD among all children age-eligible for vaccination in villages where HRV was introduced to that among such children in villages where HRV was not introduced. Total effectiveness among vaccinees and indirect effectiveness were also evaluated. In all, 6,527 infants were age-eligible for vaccination in 71 HRV villages, and 5,791 in 71 non-HRV villages. In HRV villages, 4,808 (73.7%) infants received at least one dose of HRV. The incidence rate of ARD was 4.10 cases per 100 person-years in non-HRV villages compared to 2.8 per 100 person-years in HRV villages, indicating an overall effectiveness of 29.0% (95% CI, 11.3% to 43.1%). The total effectiveness of HRV against ARD among vaccinees was 41.4% (95% CI, 23.2% to 55.2%). The point estimate for total effectiveness was higher against ARD during the first year of life than during the second (45.2% versus 28.9%), but estimates for the second year of life lacked precision and did not reach statistical significance. Indirect effects were not detected. To check for bias in presentation to treatment facilities, we evaluated the effectiveness of HRV against acute diarrhea associated with enterotoxigenic Escherichia coli; it was 4.0% (95% CI, -46.5% to 37.1%), indicating that bias likely was not introduced. Thirteen serious adverse events were identified among recipients of HRV, but none were considered related to receipt of study vaccine. The main limitation of this study is that it was an open-label study with an observed-only control group (no placebo).
The two-dose HRV rotavirus vaccination program significantly reduced medically attended ARD in this low-resource population in Asia. Protection among vaccinees was similar to that in other low-resource settings. In low-resource populations with high rotavirus incidence, large-scale vaccination across a wide population may be required to obtain the full benefit of rotavirus vaccination, including indirect effects.
ClinicalTrials.gov NCT00737503.
Abstract
Low- and middle-income countries face a high burden of typhoid and paratyphoid fever due to poor water quality and inadequate sanitation. The World Health Organization (WHO) recommends the ...use of typhoid conjugate vaccines (TCV) in endemic settings and Gavi, the Vaccine Alliance, supports TCV introduction. There are currently 2 WHO-prequalified TCVs with Typbar TCV introduced in Pakistan, Liberia, and Zimbabwe. Countries should assess disease burden and consider introduction of TCV for programmatic use. Several paratyphoid vaccine candidates are in early stages of development. An effective bivalent vaccine would be the most efficient way to control typhoid and paratyphoid fever.
Thirty-four adults received two 100-μg injections of Moderna’s mRNA SARS-CoV-2 vaccine, and serum anti–spike protein and neutralizing antibody titers were measured at day 119 — 90 days after the ...second injection. By three different assays, binding and neutralizing antibody titers declined slightly but remained elevated and higher than titers in convalescent plasma.
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