Research Content Recommendation
01
Real-World Evidence on the Effectiveness of Influenza Vaccination During Pregnancy in Preventing Influenza-like Illness: A Retrospective Cohort Study in Gansu Province
This study, published in the Chinese Journal of Vaccines and Immunization, aimed to evaluate the vaccine effectiveness (VE) of influenza vaccination (InfV) during pregnancy in preventing influenza-like illness (ILI) among pregnant women in Gansu Province, China.
Using data from the provincial electronic medical record system and the immunization program information system, a retrospective matched cohort was constructed for the influenza seasons from 2019 to 2021. The cohort included pregnant women who received InfV during pregnancy and were followed for ILI episodes within six months postpartum. A total of 246,904 pregnant women were included, of whom 1,150 received InfV during pregnancy and 245,754 did not. The adjusted VE and its 95% confidence interval (CI) were estimated using a log-binomial model.
The incidence of ILI was 4.70% (54/1,150) in the vaccinated group and 6.91% (16,990/245,754) in the unvaccinated group. The adjusted overall VE of InfV in preventing ILI among pregnant women was 33.55% (95% CI: 12.71%–49.41%). Subgroup analysis showed higher VE among women aged 30–45 years (38.25%), with urban residence (33.03%), and having a bachelor degree or above (31.87%).
The findings indicate that influenza vaccination during pregnancy can effectively reduce the incidence of ILI among pregnant women, with particularly notable protection observed in those aged 30–45 years. The study recommends strengthening health education for pregnant women and their families regarding influenza vaccination, in order to improve immunization coverage and enhance maternal and infant health protection.
https://doi.org/10.19914/j.CJVI.2024071
02
Sustained suppression of vaccine-serotype colonization following a “1+1” schedule of 10-valent and 13-valent pneumococcal conjugate vaccine (PCV) in South African children aged 3, 4, and 5 years: a single-centre, open-label, randomized trial
This study, published in Expert Review of Vaccines, examined whether a single priming dose followed by a booster dose (1+1 schedule) could provide durable protection against pneumococcal disease in children, comparable to traditional vaccination schedules.
In an open-label study, children were randomized through block randomization into one of six study arms to receive a single priming dose of PCV10 or PCV13 at 6 or 14 weeks of age, or a two-dose primary series. All groups received a booster dose at 9 months of age. Between January 9, 2017 and August 8, 2020, nasopharyngeal swabs were collected during three annual follow-up visits. Using a multiplex nanofluidic qPCR assay and simple logistic regression analysis, the study assessed and compared overall, vaccine-serotype (VT), and non-vaccine serotype (NVT) Streptococcus pneumoniae colonization at ages 3, 4, and 5 years across the different dosing groups.
The results showed that, compared to the two-dose primary schedule, a single priming dose of PCV10 or PCV13 followed by a booster in infancy resulted in similar overall, VT, and NVT pneumococcal colonization through to 5 years of age. These findings support UK modeling which suggests that transitioning from a 2+1 to a 1+1 schedule is unlikely to lead to an increase in pneumococcal disease in later childhood.
In settings such as South Africa, where PCV immunization programs are well-established and the risk of PCV13-type colonization and subsequent disease is low, the findings support transitioning to a 1+1 schedule for PCV13. A reduced-dose schedule may decrease the number of injections administered to children and reduce PCV procurement costs, potentially freeing up resources for introducing other vaccines into the immunization program.
https://doi.org/10.1080/14760584.2024.2417856
03
Fractional Doses of Pneumococcal Conjugate Vaccine — A Noninferiority Trial
This study, published in The New England Journal of Medicine, investigated whether fractional-dose regimens of the 10-valent and 13-valent pneumococcal conjugate vaccines (PCV10 [GSK] and PCV13 [Pfizer]) are noninferior to standard full-dose schedules with respect to immunogenicity, and evaluated the prevalence of vaccine-serotype pneumococcal carriage.
In this randomized, controlled trial, healthy infants in Kenya were allocated to seven equally sized groups. Participants in groups A through F received either fractional or full doses of PCV10 or PCV13, administered according to a two-dose primary series followed by a booster dose. Group A received a full dose of PCV13; group B received 40% of the full PCV13 dose; group C, 20% of the full PCV13 dose. Group D received a full dose of PCV10; group E, 40% of the full PCV10 dose; and group F, 20% of the full PCV10 dose. Group received three full primary doses of PCV10 without a booster.
Immunogenicity was assessed at two time points: 4 weeks after completion of the primary series, and 4 weeks after administration of the booster dose. Noninferiority was defined as a difference of no more than 10%points in the proportion of participants achieving a prespecified threshold response post–primary series, or as a geometric mean concentration (GMC) ratio for IgG antibodies greater than 0.5 post–booster dose. A regimen was considered noninferior if this criterion was met for at least 8 of 10 serotypes in the PCV10 groups, or at least 10 of 13 serotypes in the PCV13 groups. Nasopharyngeal carriage of vaccine serotypes was assessed at 9 and 18 months of age.
In the per-protocol analysis, 40% of the full PCV13 dose met the noninferiority threshold for 12 of 13 serotypes after the primary series, and for all 13 serotypes following the booster dose. In contrast, the 20% PCV13 dose and both 40% and 20% PCV10 doses failed to meet the prespecified noninferiority criteria. Vaccine-serotype carriage rates at 9 and 18 months of age were comparable across PCV13 groups.
These findings indicate that, within a three-dose schedule (two primary doses and one booster), a 40% fractional dose of PCV13 elicits immunogenicity that is noninferior to that of the standard full-dose regimen across all included serotypes. Lower fractional doses of both PCV13 and PCV10 did not demonstrate noninferiority. In low- and lower-middle-income countries approaching transition from Gavi support, and in middle-income countries ineligible for Gavi assistance, a three-dose regimen of 40% PCV13 may represent a viable and cost-effective alternative to full-dose schedules.
https://doi.org/10.1056/NEJMoa2314620
04
Effect of Rotavirus Vaccination on the Burden of Rotavirus Disease and Associated Antibiotic Use in India: A Dynamic Agent-Based Simulation Analysis
This study, published in Vaccine, investigated the impact of rotavirus vaccination on the burden of rotavirus disease and related antibiotic use in India. Rotavirus is one of the leading causes of diarrhea among infants and young children in many low- and middle-income countries (LMICs). In 2016, India launched a childhood rotavirus vaccination program in four states, which was expanded nationwide by 2019.
The study employed a dynamic agent-based model simulating rotavirus transmission among children under five years of age. Based on different vaccine coverage scenarios under the Universal Immunization Programme (UIP), the model simulated rotavirus transmission across Indian districts. Population characteristics derived from the National Family Household Survey (NFHS) were used to calibrate the model. The analysis estimated the effects of rotavirus vaccination on disease burden and antibiotic use at the national level, across individual states, and within household wealth quintiles.
The results indicated that since the introduction of rotavirus vaccines, the incidence of rotavirus infection among children under five in India has declined by 33.7% (prediction interval: 30.7–36.0%). Antibiotic misuse attributable to rotavirus decreased by 21.8% (18.6–25.1%), and rotavirus-associated mortality in this age group was reduced by 38.3% (31.3–44.4%). Among children under five, rotavirus-related antibiotic use accounted for 7.6% (7.5–7.9%) of total antibiotic consumption; in the absence of vaccination, this proportion was estimated to increase to 9.6% (9.4–9.9%). Projections further suggested that increasing national vaccine coverage to 68.1% (63.1–76.4%) would reduce rotavirus incidence to fewer than one case per 100,000 children under five.
The study concludes that expanding rotavirus vaccine coverage can substantially reduce unnecessary antibiotic use in India and yield significant public health benefits.
https://doi.org/10.1016/j.vaccine.2024.126211
05
Exposure to Pollutants and Vaccine Effectiveness: A Systematic Review
This article, published in Vaccines, addresses how harmful substances released by human activities contaminate air, water, and soil. In contemporary society, exposure to such environmental pollutants has become nearly unavoidable. Therefore, understanding the potential influence of these compounds on vaccine-induced immune responses is of particular importance.
This systematic review was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. It included observational, semi-experimental, and experimental studies published in either Italian or English that investigated the effects of environmental pollutant exposure on antibody responses induced by vaccination. A total of 41 studies were included, focusing primarily on the impact of pollutants on vaccine-related antibody production. The vaccines examined included those against mumps, measles, rubella, diphtheria, tetanus, hepatitis A and B, Haemophilus influenzae type B, influenza, tuberculosis, pertussis, Japanese encephalitis, poliomyelitis, and COVID-19. The most frequently studied pollutants were heavy metals, polychlorinated biphenyls (PCBs), and per- and polyfluoroalkyl substances (PFASs), and the most common method employed was human biomonitoring through serum or blood sample analysis.
The review findings indicated that the majority of studies observed associations between pollutant exposure and reduced antibody responses. Sixteen studies specifically investigated the relationship between PFAS exposure and human vaccine responses. Eleven studies focusing on heavy metals reported immune stimulation effects followed by hypersensitivity reactions, allergies, and autoimmune disorders; other studies documented immunosuppression, as well as increased risks of infection and cancer. Among eight studies examining the effects of maternal or early-life PCB exposure, six reported significantly diminished vaccine-induced immune responses in children.
To conclude, the available evidence underscores the negative impact of environmental pollution on the human immune system, suggesting that such exposure may impair the efficacy of active immunization and compromise the effectiveness of vaccination programs.
https://doi.org/10.3390/vaccines12111252
06
The Potential Impact of a Single-Dose HPV Vaccination Schedule on Cervical Cancer Outcomes in Kenya: A Mathematical Modelling and Health Economic Analysis
This study, published in Vaccines, assessed the potential health and economic impact of adopting a single-dose human papillomavirus (HPV) vaccination strategy for cervical cancer prevention in Kenya. Evidence suggests that a single dose of the HPV vaccine can effectively prevent high-risk HPV infections that cause cervical cancer and may accelerate progress toward global cervical cancer elimination targets. Currently, Kenya implements a two-dose HPV vaccination schedule. This study conducted a cost-effectiveness analysis of a single-dose strategy using mathematical modelling.
A validated compartmental transmission model of HPV and HIV was employed to evaluate various vaccination strategies from the payer’s perspective. These included one- or two-dose HPV vaccination for 10-year-old girls, under gradually increasing coverage levels (0%, 70%, 77%, and 90%). Additionally, the study modelled supplemental single-dose strategies, including catch-up vaccination for adolescent girls and young women, and universal vaccination for all children by age 10. These supplemental strategies were assumed to be financed using cost savings from switching from a two-dose to a single-dose schedule over the first five years. All costs and health outcomes were discounted at an annual rate of 3%, and incremental cost-effectiveness ratios (ICERs) were calculated per disability-adjusted life year (DALY) averted.
The results indicated that all single-dose strategies and the two-dose strategy at 90% coverage were on the efficiency frontier, dominating other two-dose strategies. The ICER for the two-dose strategy at 90% coverage was US$6508.80 per DALY averted, while the single-dose strategy at the same coverage yielded a substantially lower ICER of US$197.44 per DALY averted. Transitioning from a two-dose to a single-dose strategy could result in savings of approximately US$21.4 million over the first five years, which could fund an estimated 2.75 million additional HPV vaccine doses. Under the single-dose strategy with 90% coverage, the combination with catch-up vaccination for girls aged 11–24 resulted in the greatest number of DALYs averted, with an ICER of US$78.73 per DALY averted.
In summary, a single-dose HPV vaccination strategy offers both logistical and economic advantages, allowing for reinvestment of saved resources into catch-up vaccination efforts. This approach may accelerate cervical cancer elimination in Kenya and provides additional evidence supporting global efforts to achieve cervical cancer control targets.
https://doi.org/10.3390/vaccines12111248
Content Editor: Ruitong Li
Page Editor: Ruitong Li
