Revisiting the 2014-15 Disneyland measles outbreak and its influence on pediatric vaccinations

Measles Outbreak in Socioeconomically Diverse Sections: A Review

Measles outbreaks among socioeconomically weaker sections constitute a significant public health challenge. The objective is to highlight the specific vulnerabilities and contributing factors that make these communities more susceptible to measles outbreaks. Socioeconomically weaker sections, often characterized by poverty, inadequate healthcare access, overcrowding, and suboptimal immunization rates, face heightened risks of measles outbreaks. These outbreaks occur due to various interrelated factors, including limited healthcare infrastructure, low vaccine coverage, a lack of awareness about vaccination benefits, and difficulties in accessing healthcare services. The effects of measles outbreaks in socioeconomically disadvantaged areas are critical. Particularly among vulnerable groups, including newborns, expectant mothers, and malnourished people, measles increases morbidity and mortality. There is also a considerable financial impact on the healthcare system and the afflicted families. Measles outbreaks in these populations must be addressed using a diversified strategy. In order to improve vaccine coverage through targeted immunization programs, raise community vaccination awareness, and address social determinants of health, efforts should concentrate on bolstering the healthcare infrastructure. Effective epidemic control and prevention depend on coordinated efforts by healthcare practitioners, legislators, local leaders, and public health groups. Healthcare systems can lessen the impact of measles in socioeconomically disadvantaged areas and strive toward attaining equitable health outcomes for all populations by addressing the socioeconomic variables that lead to the vulnerability of measles.

Diminished measles immunity after paediatric liver transplantation-A retrospective, single-centre, cross-sectional analysis

Liver transplantation in childhood has an excellent long-term outcome, but is associated with a long-term risk of infection. Measles is a vaccine-preventable infection, with case series describing severe courses with graft rejection, mechanical ventilation and even death in liver transplant recipients. Since about 30% of liver transplanted children receive liver transplants in their first year of life, not all have reached the recommended age for live vaccinations. On the contrary, live vaccines are contraindicated after transplantation. In addition, vaccination response is poorer in individuals with liver disease compared to healthy children. This retrospective, single-centre, cross-sectional study examines measles immunity in paediatric liver transplant recipients before and after transplantation. Vaccination records of 239 patients, followed up at Hannover Medical School between January 2021 and December 2022 were analysed. Twenty eight children were excluded due to stem cell transplantation, regular immunoglobulin substitution or measles vaccination after transplantation. More than 55% of all 211 children analysed and 75% of all those vaccinated at least once are measles seropositive after transplantation-48% after one and 84% after two vaccinations-which is less than in healthy individuals. Interestingly, 26% of unvaccinated children also showed measles antibodies and about 5-15% of vaccinated patients who were seronegative at the time of transplantation were seropositive afterwards, both possibly through infection. In multivariable Cox proportional hazards regression, the number of vaccinations (HR 4.30 [95% CI 2.09-8.83], p<0.001), seropositivity before transplantation (HR 2.38 [95% CI 1.07-5.30], p = 0.034) and higher age at time of first vaccination (HR 11.5 [95% CI 6.92-19.1], p<0.001) are independently associated with measles immunity after transplantation. In contrast, older age at testing is inversely associated (HR 0.09 [95% CI 0.06-0.15], p<0.001), indicating a loss of immunity. Vaccination in the first year of life does not pose a risk of non-immunity. The underlying liver disease influences the level of measles titres of twice-vaccinated patients; those with acute liver failure being the lowest compared to children with metabolic disease. In summary, vaccine response is poorer in children with liver disease. Liver transplant candidates should be vaccinated before transplantation even if this is earlier in the first year of life. Checking measles IgG and re-vaccinating seronegative patients may help to achieve immunity after transplantation.