Challenges to global measles eradication: is it all in the timing?

Measles-mumps-rubella-vaccination at 6 months of age induces measles-specific T cell responses: a randomized controlled trial

Background

Measles is a highly contagious viral disease, particularly severe in infants. Protection in early life is provided by maternally transferred antibodies, but this period is shorter in infants of previously vaccinated mothers (PVMs) compared to infants of previously measles-infected mothers (PIMs). Earlier measles-mumps-rubella (MMR) vaccination may compensate for this. To evaluate immune responses, 6-month-old infants were randomized to receive early MMR or placebo. This study reports the cellular immune outcomes and summarizes serological and T-cell responses.

Methods

A double-blind, randomized trial involved 6540 Danish infants aged 5-7 months, eligible if birth weight exceeded 1000 grams and gestational age was ≥32 weeks. Participants were randomized 1:1 to receive M-M-RVaxPro or placebo. Blood samples were collected before intervention, four weeks after intervention, and four weeks after routine MMR at 15 months. Peripheral blood mononuclear cells (PBMCs) were prepared, and an IFN-γ specific ELISpot assay measured measles-specific T cells.

Results

Among 750 infants (341 MMR, 409 placebo) in the cellular immunogenicity trial, a significant cellular immune response was observed one-month post-intervention in the MMR group compared to placebo (geometric mean ratio [GMR]: 12.3; 95% CI: 6.9-21.9). The cellular conversion rate (CCR) in the MMR group was 45%, comparable to the previously reported seroconversion rate. However, following routine MMR at 15 months, a reduced cellular response was observed in the early MMR group (GMR: 0.6; 95% CI: 0.3-0.9). Post-routine MMR, CCRs were 66% (MMR) and 74% (placebo). The immune conversion rate (ICR, defined as seroconversion and/or T-cell response) reached 99% in both groups post-routine MMR.

Conclusion

Early MMR at 6 months elicited significant measles-specific cellular responses, though the CCR was lower than after routine MMR at 15 months. However, when combining serological and cellular responses, 99% of infants achieved immune conversion by 15 months. Early MMR could help reduce measles burden in infants in endemic settings without compromising subsequent immunizations.

Clinical trial registration

ClinicalTrials.gov, identifier NCT03780179, EudraCT 2016-001901-18.

An Application of an Initial Full Value of Vaccine Assessment Methodology to Measles-Rubella MAPs for Use in Low- and Middle-Income Countries

Measles and rubella micro-array patches (MR-MAPs) are a promising innovation to address limitations of the current needle and syringe (N&S) presentation due to their single-dose presentation, ease of use, and improved thermostability. To direct and accelerate further research and interventions, an initial full value vaccine assessment (iFVVA) was initiated prior to MR-MAPs entering phase I trials to quantify their value and identify key data gaps and challenges. The iFVVA utilized a mixed-methods approach with rapid assessment of literature, stakeholder interviews and surveys, and quantitative data analyses to (i) assess global need for improved MR vaccines and how MR-MAPs could address MR problem statements; (ii) estimate costs and benefits of MR-MAPs; (iii) identify the best pathway from development to delivery; and (iv) identify outstanding areas of need where stakeholder intervention can be helpful. These analyses found that if MR-MAPs are broadly deployed, they can potentially reach an additional 80 million children compared to the N&S presentation between 2030-2040. MR-MAPs can avert up to 37 million measles cases, 400,000 measles deaths, and 26 million disability-adjusted life years (DALYs). MR-MAPs with the most optimal product characteristics of low price, controlled temperature chain (CTC) properties, and small cold chain volumes were shown to be cost saving for routine immunization (RI) in low- and middle-income countries (LMICs) compared to N&S. Uncertainties about price and future vaccine coverage impact the potential cost-effectiveness of introducing MR-MAPs in LMICs, indicating that it could be cost-effective in 16-81% of LMICs. Furthermore, this iFVVA highlighted the importance of upfront donor investment in manufacturing set-up and clinical studies and the critical influence of an appropriate price to ensure country and manufacturer financial sustainability. To ensure that MR-MAPs achieve the greatest public health benefit, MAP developers, vaccine manufacturers, donors, financiers, and policy- and decision-makers will need close collaboration and open communications.

Morbillivirus: A highly adaptable viral genus

Over the course of human history, numerous diseases have been caused by the transmission of viruses from an animal reservoir into the human population. The viruses of the genus Morbillivirus are human and animal pathogens that emerged from a primordial ancestor a millennia ago and have been transmitting to new hosts, adapting, and evolving ever since. Through interaction with susceptible individuals, as yet undiscovered morbilliviruses or existing morbilliviruses in animal hosts could cause future zoonotic diseases in humans.

The association between the density of vaccination workers and immunization coverage in Zhejiang province, East China

Background: We aimed to evaluate whether the density of vaccination workers was associated with the immunization coverage in Zhejiang province.Methods: The immunization coverage of measles-containing vaccine (MCV), the third dose of diphtheria, tetanus, and pertussis combined vaccine (DTP3), and the third dose of poliomyelitis vaccine (PV3) was selected as the dependent variables. Immunization coverage data of children aged 13-23 months were taken from the Zhejiang immunization information system (ZJIIS). The aggregate density of vaccination workers was an independent variable in one set of regressions, while the full-time and part-time vaccination workers were adopted separately in other sets.Results: The density of total vaccination workers was positively and significantly associated with the immunization coverage (MCV: AOR = 3.36; DTP3: AOR = 2.68; PV3: AOR = 2.37). However, when the effects of full-time vaccination workers and part-time vaccination workers were assessed separately, we only found that the density of full-time vaccination workers was positively and significantly associated with the immunization coverage (MCV: AOR = 5.59; DTP3: AOR = 4.13; PV3: AOR = 3.28). The proportion of migrant children < 7 years and Land area were found as negative and significant factors for immunization coverage.Conclusions: A higher density of vaccination workers could improve the availability of vaccination services and immunization coverage. We recommended that government or other non-government organization should, apart from vaccine-related assistance, focus their efforts on human resources for vaccination.

Should there be a World Health Assembly resolution for malaria eradication? Opinion against

A resolution for eradicating malaria, if passed by the World Health Assembly (WHA), will have a distracting effect on all countries with malaria. The continued prevalence of malaria is indicative of weak public health infrastructure. True, smallpox was eradicated by international efforts following WHA resolution: the success factor was primary prevention using a safe and effective vaccine. A resolution to eradicate polio was passed in 1988, with a target year of 2000, but even in 2019 success is not within reach. Public health experts are hesitant to move forward with measles eradication before polio is eradicated. Country by country elimination of malaria is a better way, ensuring the strengthening of public health infrastructure, with many other health benefits.