Safety of measles and pertussis-containing vaccines in children with autism spectrum disorders

ObjectivesTo determine whether children aged 4–7 years with a diagnosis of autism spectrum disorders (ASD) were at increased risk of fever, febrile seizures, or emergency department (ED) visits following measles- or pertussis-containing vaccines compared with children without ASD.MethodsThe study included children born between 1995–2012, aged 4–7 years at vaccination, and members of six healthcare delivery systems within Vaccine Safety Datalink. We conducted self-controlled risk interval analyses comparing rates of outcomes in risk and control intervals within each group defined by ASD status, and then compared outcome rates between children with and without ASD, in risk and control intervals, by estimating difference-in-differences using logistic regressions.ResultsThe study included 14,947 children with ASD and 1,650,041 children without ASD. After measles- or pertussis-containing vaccination, there were no differences in association between children with and without ASD for fever (ratio of rate ratio for measles-containing vaccine = 1.07, 95% CI 0.58–1.96; for pertussis-containing vaccine = 1.16, 95% CI 0.63–2.15) or ED visits (ratio of rate ratio for measles-containing vaccine = 1.11, 95% CI 0.80–1.54; for pertussis-containing vaccine = 0.87, 95% CI 0.59–1.28). Febrile seizures were rare. Pertussis-containing vaccines were associated with small increased risk of febrile seizures in children without ASD.ConclusionChildren with ASD were not at increased risk for fever or ED visits compared with children without ASD following measles- or pertussis-containing vaccines. These results may provide further reassurance that these vaccines are safe for all children, including those with ASD.     

Estimating the number of US children susceptible to measles resulting from COVID-19-related vaccination coverage declines

Measles elimination hinges on vaccination coverage remaining above 95% to retain sufficient community protection. Recent declines in routine measles vaccinations due to the COVID-19 pandemic coupled with prior models indicating the country was close to the 92% herd immunity benchmark are a cause for concern. We evaluated population-level measles susceptibility in the US, including sensitivity analyses accounting for pandemic-related impacts on immunization. We estimated the number of children aged 0–18 currently susceptible to measles and modeled susceptibility proportions in decreased vaccination scenarios. Participants were respondents to the NIS-Teen survey between 2008 and 2017 that also had provider-verified vaccination documentation. The exposure of interest was vaccination with a measles-containing vaccine (MCV), and the age at which they were vaccinated for all doses given. Using age at vaccination, we estimated age-based probabilities of vaccination and modeled population levels of MCV immunization and immunity vs. susceptibility. Currently, 9,145,026 children (13.1%) are estimated to be susceptible to measles. With pandemic level vaccination rates, 15,165,221 children (21.7%) will be susceptible to measles if no attempt at catch-up is made, or 9,454,436 children (13.5%) if catch-up vaccinations mitigate the decline by 2–3%. Models based on increased vaccine hesitancy also show increased susceptibility at national levels, with a 10% increase in hesitancy nationally resulting in 14,925,481 children (21.37%) susceptible to measles, irrespective of pandemic vaccination levels. Current levels of measles immunity remain below herd immunity thresholds. If pandemic-era reductions in childhood immunization are not rectified, population-level immunity to measles is likely to decline further.     

Antibodies to measles,mumps, and rubella virus in Thai children after two-dose vaccination at 9 months and 2.5 years: A longitudinal study

IntroductionThailand changed the schedule of childhood measles–mumps–rubella (MMR) vaccination in 2014, moving the second dose from the age of 6 years to 2.5 years. There are currently no data on antibody responses to the MMR vaccine since this recommendation.Material and methodsWe investigated antibody responses in a cohort of children who received two doses of MMR vaccine at the ages of 9 months and 2.5 years that was originally established to evaluate antibody levels to Bordetella pertussis antigens (ClinicalTrials.gov no. NCT02408926). Infants were born to mothers who previously received tetanus–diphtheria–acellular pertussis vaccine at 27–36 weeks of gestation. Anti-measles, -mumps, and -rubella virus IgG levels were measured at birth (cord blood) and the ages of 2 and 7 months (before the first MMR vaccination); 18 and 24 months (9 and 15 months, respectively, after the first dose); and 36 months (6 months after the second dose) using commercially available enzyme-linked immunosorbent assay kits.ResultsAt 7 months of age, 96.2%, 99.6%, and 98.8% of infants had no protection against measles, mumps, and rubella, respectively. Levels of antibody against all three antigens increased significantly after the first but not the second dose. At 6 months after two-dose vaccination, 97.4%, 84.8%, and 78.7% of children remained seroprotected against measles, mumps, and rubella, respectively.ConclusionsMaternally derived antibodies to measles, mumps, and rubella virus disappeared by the age of 7 months in Thai children. Two-dose MMR vaccination at 9 months and 2.5 years of age induced robust immune responses against these viruses.     

Cost analysis of supplemental immunization activities to deliver measles immunization to children in Anambra state,south-east Nigeria

BackgroundMeasles immunization is critical for reducing the societal burden of the disease, especially among children. However, the costs of the measles supplemental immunization activities, which are the main vaccine deployment strategy, are usually high and financing such immunization activities is a serious challenge in Nigeria. In Nigeria, little or no information exists on the costs of measles supplemental immunization activity for planning and sustenance of immunization programmes. This study aimed to determine the cost per child immunized and cost structure of a follow-up supplemental immunization activity (SIA) for measles immunization to children.MethodData on costs and outputs of SIA were collected from six Local Government area (LGAs) immunization offices in Anambra state, southeast Nigeria. The ingredient approach was used for costing, based on the providers’ perspective. The sample results were extrapolated to state estimates using volume weighted mean method. The major indicator considered was cost per child immunized. Two-way sensitivity analysis was used to test the robustness of the results.ResultThe cost per child immunized through SIA was $1.37 and the cost per child for operational cost only was $0.81. The total cost of the SIA for the sample was $345,069.35 and the operational cost was $204,969.46. The cost of personnel (43.99%) and vaccine (36.22%) contributed the highest percentage to the total cost of SIA. The cost of personnel and transportation took the first (74.6%) and second (7.10%) highest percentages of the operational cost for the sample. The estimated total and operational costs of measles SIA for the state were $1,279,127.84 and $759,795.52 respectively.ConclusionThe cost per child immunized with measles containing vaccine through SIA is relatively high in Nigeria. There is a need to review the activities with SIA, so as to ensure that resources are efficiently allocated and used for different activities of the programme.     

Randomized study of intradermal compared to intramuscular hepatitis B vaccination in HIV-infected children without severe immunosuppression

HIV infected individuals have poorer response to hepatitis B vaccine (HBV) compared to normal host. Intradermal administration (ID) facilitates the exposure of antigen to antigen-presenting cells compared to intramuscular administration (IM).HIV-infected children aged 1-18 years with CD4% ≥ 15% or 200 cells/mm³ who had negative HBs Ag, antiHBs, and antiHBc were randomized to receive 3-dose of HBV via ID (2 μg/dose) or IM (10 μg/dose) route at months 0, 2, and 6. AntiHBs titers were measured at months 2, 6 and 7 after first HBV. AntiHBs ≥ 10 mIU/mL was considered protective and AntiHBs > 100 mIU/mL was considered good response.Participants included 41 in ID and 39 in IM arms. 64% had completed 3-doses HBV during infancy. The mean (SD) of age, nadir CD4% and current CD4% were 12 (3.3) years, 10.6 (7.9)% and 28 (8.0)% respectively. 91% were on HAART and 84% had undetectable HIV-RNA.Proportion of children with protective antiHBs in ID vs. IM group were 19.5% vs. 25.6% at month 2, 56.1% vs. 76.9% at month 6, and 90.2% vs. 92.3% at month 7 (NS, all). The geometric mean (95% confidence interval) of antiHBs titer in ID vs. IM group were 112.5 (34.4-367.6) vs. 141.2 (49.4-404.1) mIU/mL at month 2 (p = 0.74), 70.4 (39.8-124.4) vs. 132.1 (79.4-219.8) mIU/mL at month 6 (p = 0.10), and 157.0 (103.0-239.3) vs. 458.9 (324.0-647.0) mIU/mL at month 7 (p < 0.001). However, only 56.1% of the ID arm had good response to HBV compared to 82.1% in the IM arm (p = 0.01). The predictors for being a good responder to HBV were IM administration [OR 4.0, 95%CI 1.4-11.8, p = 0.012] and body weight <35 kg at baseline [OR 3.8, 95%CI 1.3-10.8, p = 0.013]. No adverse events grade 3/4 occurred.In conclusion, HIV-infected children without severe immune suppression, both ID and IM routes of HBV resulted in similar rates of protective antibody titers. However, high antibody titers to HBV were more common with IM; therefore, IM administration is preferred.     

Seroprevalences of antibodies against pertussis,diphtheria, tetanus,measles, mumps and rubella: A cross-sectional study in children following vaccination procedure in Guangzhou,China

This study investigated the concentrations and seroprevalence of immunoglobulin G (IgG) antibodies against pertussis, diphtheria, tetanus, measles, mumps and rubella among children in Guangzhou, China. We conducted a cross-sectional study focusing on the post-vaccination immune statuses of children on scheduled immunisation. Human IgG antibody against six diseases were measured using commercial enzyme-linked immunosorbent assay kits. Of 620 subjects, the male-to-female ratio was 2.04 (416/204). Seroprevalence (81.97% vs 90.20%) and IgG concentrations (686.55 IU/mL vs 884.26 IU/mL, P < 0.05) for measles, tetanus (0.94 IU/mL vs 1.21 IU/mL) and rubella (34.33 IU/mL vs 47.37 IU/mL) were all higher in females. No differences based on sex were observed in the seroprevalence and IgG concentrations for anti-pertussis antibodies, anti-diphtheria antibodies and anti-mumps. Slight increase in seroprevalence and IgG concentration occurred with anti-pertussis antibodies after primary and booster vaccinations (from 0.00% [1 m], 5.45% [6 m], to 17.14% [1.5 yr]; and from 8.57% [5 yr] to 15.79% [6 yr]). Although no booster vaccination was given after age 6 yr, the seroprevalence and IgG concentration for anti-pertussis antibodies remained relatively stable. For diphtheria, tetanus, measles and rubella, seroprevalence reached their peaks after the primary and first booster vaccination. A plateau occurred after age 1.5 yr with a declining trend in subjects >8–10 yr. The IgG concentrations of these 4 pathogens showed a dramatic increase after primary vaccination, with steadily declining trends thereafter. For mumps, subjects showed increased seroprevalence and IgG concentration after the primary mumps-containing vaccination in 1.5-yr-olds (from 7.14% to 57.14%; 52.13 IU/mL to 214.18 IU/mL); however, following that low seroprevalence levels (from 42.86% to 80.00%) were observed. The post-vaccination immune statuses against diphtheria, tetanus, measles and rubella were relatively satisfactory, compared to those against pertussis and mumps. Booster vaccination against pertussis and mumps at appropriate time should be considered.