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

Mobile Apps for Vaccination Services: Content Analysis and Quality Assessment

BACKGROUND

Vaccination services are increasingly in demand by the public, and mobile apps are an effective tool to meet that demand. However, the characteristics and quality of these apps are unknown.

OBJECTIVE

Commonly used vaccination service apps on the market were surveyed with regard to quality, service content, and user experience to evaluate and guide users.

METHODS

The Qimai Data mobile app data analytics platform was used to search for common vaccination service apps by keyword, and the WeChat and Alipay platforms were searched for apps. The apps included in the study were independently evaluated by two reviewers using the Mobile Application Rating Scale, and the service content and user experience of the apps were analyzed. The intragroup correlation coefficient between raters was used to measure interrater reliability.

RESULTS

In the app stores of the four major Android platforms and the iOS app store, 1092 and 207 apps were found, respectively; 189 WeChat applets and 30 Alipay applets were also found. A total of 29 apps was ultimately included in this study according to the inclusion criteria, including 21 independent apps, 4 WeChat applets, and 4 Alipay applets. Significant differences were found between independent apps and applets in terms of the quality score (t449.57=-5.301; P<.001) and the subjective quality score (z=-4.753; P<.001). No significant differences were found between iOS and Android platforms in terms of the quality score (t1404=-2.55; P=.80) and the subjective quality score (z=-0.137; P=.89). There was good intragroup consistency among the raters.

CONCLUSIONS

In this study, independent apps and nonindependent apps that rely on social and payment platforms for implementation were included in the vaccination services category. The overall quality of these apps was acceptable. Nonindependent running apps were found to have slightly lower scores and showed room for improvement, and scores for the participatory apps were found to be generally low overall.

Persistence of Antibodies against Measles, Mumps, and Rubella after the Two-Dose MMR Vaccination: A 7-Year Follow-Up Study

In 2014, the Expanded Program on Immunization of Thailand changed the timing of the second dose of the measles-mumps-rubella (MMR) vaccine from 4-6 years to 2.5 years, while maintaining the first dose at 9 months of age. This study aimed to examine the dynamics and durability of immune responses induced by the two-dose MMR vaccine in a group of 169 Thai children from 4 to 7 years of age (4.5 years after the second MMR dose). We followed a cohort of healthy children from a clinical trial (ClinicalTrials.gov NCT02408926) where they were administered either the Priorix vaccine (GlaxoSmithKline Biologicals, Rixensart, Belgium) or M-M-RII (Merck & Co., Kenilworth, NJ, USA) at 9 months and 2.5 years of age. Blood samples were collected annually from ages 4 to 7 years. Anti-measles, -mumps, and -rubella IgG levels were evaluated using the enzyme-linked immunosorbent assay (EUROIMMUN, Lubeck, Germany). A total of 169 children completed this study. Over the 4.5 years following the two-dose MMR vaccination, we observed a decline in the seroprotection rates against measles and mumps, but not rubella. Longitudinal monitoring of antibody persistence, among other strategies, will help predict population-level immunity and inform public health interventions to address potential future outbreaks.

A phase II/III randomised, comparative study evaluating the safety and immunogenicity of Biological E's live, attenuated Measles-Rubella vaccine in 9-12 month old healthy infants

Measles is a major cause of childhood mortality and one-third of the world's Measles deaths occur in India. Rubella causes lifelong birth defects (Congenital Rubella Syndrome). Although neither condition has a cure, the MR vaccination can successfully prevent both diseases. The safety of Biological E's live attenuated MR vaccine (BE-MR) was established in 4-5-year-old healthy children. This phase-2/3 study was conducted to assess the safety and immunogenicity of BE-MR in 9-12 month old healthy infants. Overall, 600 subjects were enrolled and equally randomized to receive either BE-MR (n = 300) or the comparator vaccine, SII MR-Vac™ (n = 300). Safety profile of BE-MR vaccine was comparable to SII MR-Vac™ with no severe or serious adverse events (AEs) reported across the study groups. The primary objective of demonstrating non inferiority by BE-MR vaccine compared to SIIL's-MR Vac™ was met. The proportion of subjects with ≥ 2-fold and ≥ 4-fold increase in antibody titre against Measles and Rubella in both the study groups was comparable. Overall, BE-MR vaccine elicited robust and protective immune response as demonstrated by high proportion of sero-protected subjects and a large increase in anti-Measles and anti-Rubella antibodies at day 42 and can be administered safely to infants below one-year of age. This study was prospectively registered with the clinical trial registry of India- CTRI/2016/07/007109.

Do adolescents need a rubella vaccination campaign? Rubella serosurvey among healthy children in Hangzhou, China

The aim of this study was to evaluate the seroprevalence of rubella antibodies and factors associated with antibody seropositivity after vaccination among healthy children aged 14 and below. A multi-stage stratified random sampling method was employed to recruit participants for the rubella serological test. An enzyme-linked immunosorbent assay method was used to detect human IgG antibodies with avidity for rubella virus in the sera of participants. Univariate and multivariate analyses were used to analyze associations between variables. A total of 778 subjects were included in the subsequent analysis. The overall positive rate of rubella antibody was 83.0% (95%CI: 80.2-85.5%), and the overall geometric mean concentration (GMC) was 58.05 IU/ml. In multivariate analysis, gender, residence, birth year group, and time since the last rubella-containing vaccines (RCV) vaccination were significantly associated with the seroprevalence of rubella antibodies. Our study showed a decreasing trend in rubella antibody positivity and GMC in the population aged five to 14 years. Therefore, we recommend a catch-up dose of RCV for adolescents and young people aged over 14 years not yet vaccinated.

Evaluation of the effect of maternally derived antibody on response to MMR vaccine in Thai infants

BACKGROUND

Although the number of measles cases declined globally in response to anti-measles immunisation campaigns, measles has re-emerged. A review of current vaccination policies is required to improve measles elimination strategies.

METHODS

A pseudotype-based virus neutralisation assay (PVNA) was used to measure neutralising antibody titres in serum samples collected from Thai infants at six timepoints before and after two-doses of MMR (1&2) vaccination (ClinicalTrials.gov no. NCT02408926). Vesicular stomatitis virus (VSV) luciferase pseudotypes bearing the haemaglutinin (H) and fusion (F) glycoproteins of measles virus (MeV) were prepared. Serial dilutions of serum samples were incubated with VSV (MeV) pseudotypes and plated onto HEK293-human SLAM1 cells; the neutralising antibody titre was defined as the dilution resulting in 90% reduction in luciferase activity.

RESULTS

Neutralising antibody titres in infants born with high levels of maternal immunity (H group) persisted at the time of the first MMR vaccination, and those infants did not respond effectively by developing protective titres. In contrast, infants with lower maternal immunity (L group) developed protective titres of antibody following vaccination. Responses to the second MMR vaccination were significantly higher (P = 0.0171, Wilcoxon signed-rank test) in the H group. The observed correlation between anti-MeV IgG level and neutralising antibody titre in Thai infants indicates the possibility of using rapid IgG testing as a surrogate measure for neutralising activity to define clinical protection levels within populations.

CONCLUSION

These results demonstrate that varying the timing of the first MMR immunisation according to the level of acquired maternal immunity could increase vaccination immunogenicity and hence accelerate measles eradication.

Neutralizing antibody against Enterovirus-A71 in Thai children: A longitudinal study from birth to age 4 years

Thailand is one of the countries in the Asia-pacific region that has been most affected by the Enterovirus-A71 (EV-A71) epidemic. An individual who is susceptible to EV-A71 may also be infected asymptomatically, thus, a serological assay is a useful tool to estimate the cumulative incidence of infection in the community and to provide guidance for vaccination scheduling. There have been several candidate EV-A71 vaccines, of which three have been approved and licensed in China. The population target for EV-A71 vaccine is children younger than three years of age. In Thailand, there are limited data available on the seroprevalence of EV-A71 neutralizing (NT) antibodies and the timing of seroconversion in children. This study aims to investigate the seroprevalence and seroconversion rate of EV-A71 NT antibody in a cohort of Thai children. Sera were collected at the King Chulalongkorn Memorial Hospital in Bangkok, Thailand from 100 children between 2015 and 2020. Maternal sera were collected on the day of delivery. Serum samples from children were collected at birth (month 0) and at 2, 7, 18, 24, 36, and 48 months of age to test for EV-A71 NT antibody titers using an enzyme-linked immunosorbent assay (ELISA)-based microneutralization test. The seroprotection rate (NT antibody ≥1:16) in children at months 0, 2, 7, 18, 24, 36, and 48 was 81.0%, 60.0%, 9.0%, 10.0%, 13.0%, 17.0%, and 37.1%, respectively. The seroprotection rate was lowest at month 7 due to waning of the maternal antibody and the immunity of children increased with increasing age. At 48 months of age, less than 40% of children were seroprotected. Children at the age of 6 months should be considered a primary target for vaccination.