Prevalence of prolonged otitis media with effusion among 2 to 3 years old Cameroonian children in the era of 13-valent pneumococcal conjugate vaccines

Objectives

There is data scarcity on the overall effects of pneumococcal conjugate vaccines (PCVs) on otitis media (OM) in low- and middle-income countries. The impact of the 13-valent PCV (PCV13) program on OM was evaluated in Cameroon where infant vaccination was implemented in July 2011 using a 3-dose primary series at 6, 10 and 14 weeks of age.

Methods

Through community-based surveillance, we used a retrospective cohort study design to assess OM prevalence among PCV13-vaccinated children aged 24 to 36 months in 2015. This was compared with a 2013 age-matched cohort of PCV13-unvaccinated children. OM was diagnosed by clinical inspection for chronic suppurative OM (CSOM) and tympanometry for OM with effusion (OME). CSOM was defined as draining of the middle ear with duration of more than 2 weeks and prolonged OME was defined as a flat 'type B' tympanogram. PCV13-vaccinated and PCV13-unvaccinated cohorts were compared by calculating prevalence odds ratios for OM and baseline characteristics.

Results

Altogether, 111 OM cases were identified; 42/433 (9.7%) in the PCV13-unvaccinated in 2013 and 69/413 (16.7%) in the PCV13-vaccinated cohort in 2015. In the 2013 baseline survey, 3/433 (0.7%) children were identified with unilateral CSOM compared to 9/413 (2.2%) in the PCV13-vaccinated cohort in 2015. Bilateral prolonged OME was diagnosed in 7/433 (1.6%) PCV13-unvaccinated children and in 12/413 (2.9%) in PCV13-vaccinated children. Proportions of children with unilateral prolonged OME were 31/433 (7.2%) in the PCV13-unvaccinated group compared with 48/413 (11.6%) in the PCV13-vaccinated group. Multivariate logistic regression analysis showed evidence that PCV13-vaccinated children in 2015 had 40% less risk of contracting OM compared to PCV13-unvaccinated children in 2013 (adjusted prevalence odds ratios = 0.60 [95% confidence interval: 0.38 to 0.94], P = 0.025). Additionally, attributable proportion estimates show that, 58% of OM infections among the PCV13-vaccinated group would still have occurred despite PCV13 vaccination.

Conclusion

Our findings provide significant evidence on the effect of PCV13 in decreasing OM or OME among children in this age group. It also supports justification for government's continuation of PCV13 immunization program in the absence of GAVI's funding. Further research is needed to assess the long-term impact of the PCV13 program on in OM Cameroon.

The prevalence of hepatitis B core antibody in vaccinated Chinese children: A hospital-based study

BACKGROUND & AIMS

After nearly 30 years of immunization, there is little known about the prevalence of hepatitis B core antibody (anti-HBc) in Chinese children. The clinical significance of anti-HBc would be more and more important. In this study, we had tried to analyse the prevalence of anti-HBc in vaccinated Chinese children, exploring the post-immunization status based on a large sample sized investigation.

METHODS

Proportions of anti-HBc were analysed among 215,627 hospitalized Chinese children immunized with HBV vaccination in this study.

RESULTS

The proportions of anti-HBc were divided into 3 stages: 36.6% in 0-year-old group, followed by 1- to 10-year-old which stayed relatively stable (5.69 ± 0.40%, [4.86-6.28%]), and significant increasing within 11- to 16-year-old (7.80 ± 1.24%, [6.62-9.74%]), meanwhile, similar changes of HBsAg were showed in the corresponding ages, and significantly increased in children older than 9-year (1.40%, [1.00-2.04%]), comparing with 0.30% in 0-year-old, 0.55 ± 0.13% (0.30-0.64%) in 1- to 9-year-old. The average level of anti-HBc maintains 5.99% in children aged 1- to 16-year with 0.63% for HBsAg.

CONCLUSION

This is the first study of the prevalence of anti-HBc in vaccinated Chinese children: 36.6% of anti-HBc-positivity was found in 0-year-old group, which could be maternal in origin. Relatively high prevalence of anti-HBc may not be ignored in children aged 1- to 16-year-old. Strangely, our data also showed that HBV breakthrough infection would occur in immunized Chinese children older than 9-year-old, and more attention is needed on those children.

Safety and immune response to a challenge dose of hepatitis B vaccine in healthy children primed 10years earlier with hexavalent vaccines in a 3, 5, 11-month schedule: An open-label, controlled, multicentre trial in Italy

BACKGROUND AND AIMS

The strategy of vaccinating infants to prevent hepatitis B virus infection in adolescence or adulthood requires durable immunity. This study investigated responses to a challenge dose of monovalent hepatitis B vaccine in children primed with three doses of either Hexavac® or Infanrix hexa® 10years earlier during infancy.

METHODS

This open-label, controlled, multicentre study conducted in Italy, enrolled 751 healthy pre-adolescents (aged 11-13years) who were given either Hexavac (n=409) or Infanrix hexa (n=342) at 3, 5 and 11months of life. All participants received a challenge dose of a monovalent hepatitis B vaccine (HBVaxPro® 5µg). The concentrations of antibodies to hepatitis B surface antigen (anti-HBs) were measured before and 1month after the challenge dose. The analysis was descriptive and no formal hypothesis was tested.

RESULTS

One month post-challenge, 331 participants in the Hexavac cohort [83.6%, 95% CI: 79.6; 87.1] and 324 in the Infanrix hexa cohort [96.4%, 95% CI: 93.8; 98.1] had anti-HBs concentrations ≥10mIU/mL. Before the challenge dose, an anti-HBs concentration of ≥10mIU/mL was found in 94 children in the Hexavac cohort [23.9%, 95% CI: 19.7; 28.4] and in 232 children in the Infanrix hexa cohort [69%, 95% CI: 63.8; 74.0]. Among children with a pre-challenge anti-HBs concentration of <10mIU/mL, 236 [78.7%, 95% CI: 73.6; 83.2] in the Hexavac cohort and 92 [88.5%, 95% CI: 80.7; 93.9] in the Infanrix hexa cohort achieved protective anti-HBs antibody concentrations. No evidence of active hepatitis B disease was observed in either group, and the HBVaxPro challenge dose was well tolerated.

CONCLUSIONS

These data confirm that immune memory persists in a high percentage of children (>80%) at least 10years after a two-dose primary and booster vaccination schedule with a hexavalent vaccine (Hexavac or Infanrix hexa).

TRIAL REGISTRATION

EudraCT Number: 2013-001602-28; clinicaltrials.gov: NCT02012998.