Measles, mumps, rubella prevention: how can we do better?

A review of safety and immunogenicity of a novel measles, mumps, rubella (MMR) vaccine

Measles, mumps, and rubella (MMR) are highly infectious viral diseases affecting young children and have high secondary attack rates. Present MMR vaccines show consistent seroconversion rates for anti-measles and anti-rubella antibodies with variable responses for anti-mumps antibodies. Most common strains for MMR vaccines, currently available in India, are the Edmonston-Zagreb measles strain, Leningrad Zagreb (L-Z) mumps strain, and the RA 27/3 rubella strain. L-Z strain of mumps virus has been found to be associated with aseptic meningitis by different studies from different parts of the world including India. Recently, a novel freeze-dried MMR vaccine developed by Zydus Lifesciences (Zyvac MMR) contains Edmonston Zagreb measles strain, Hoshino mumps strain, and RA 27/3 rubella strain. The Hoshino strain is WHO approved and was found to induce interferon gamma production. This review article aims to provide a comprehensive appraisal of the data available on the safety and immunogenicity of the novel MMR vaccine.

Determinants of second-dose measles vaccination dropout in Ethiopia: A community-based matched case-control study

Background

Measles vaccination is the most important public health intervention and a cost-effective strategy to reduce morbidity and mortality in under-five children. Although Ethiopia's government developed a measles elimination strategic plan by 2020, the full coverage of immunization was 43 %. Therefore, this study aimed to identify determinants of second-dose measles vaccination (MCV2) dropout among children aged 24-35 months in East Bale Zone, Ethiopia.

Method

A community-based matched case-control study was conducted among 351 children (117 cases and 234 controls). Children who received the first dose of measles vaccine but did not receive the second dose were cases, and children who received both doses of measles vaccine were control. The matches were based on age and residence. The data were collected using a structured questionnaire, entered into Epi Data 3.1, cleaned, exported, and analyzed using Stata version 16.1. A multivariable conditional logistic regression analysis was performed. Variables with a P value of <0.05 were considered significant determinants of the dependent variable at the 95 % confidence level.

Results

Mothers who were unable to read and write (mAOR: 4.0; 95 % CI: 1.59-10.2), did not receive counseling (mAOR: 3.19; 95 % CI: 1.62-6.27), spent ≥30 min to reach health facilities (mAOR; 2.76, 95 % CI: 1.25-6.1), and did not attend postnatal care (mAOR; 3.46, 95 % CI: 1.58-7.57) were significantly and positively associated with second-dose measles vaccination dropout. In addition, mothers who had poor knowledge of second-dose measles vaccination (mAOR; 3.20, 95 % CI: 1.50-6.70) and waited more than an hour for measles vaccination at health facilities (mAOR; 2.61, 95 % CI: 1.0-6.20) were significantly more likely to experience second-dose measles vaccine dropout.

Conclusions

The key factors associated with second-dose measles vaccination dropout are maternal illiteracy, lack of PNC, inadequate maternal knowledge and poor counseling about MCV2 vaccination, long distances travel to healthcare facilities and extended waiting times at vaccination providing sites. Health extension workers emphasize strengthening home visit programs in catchment households to improve mothers' awareness of measles vaccination.

Case Ascertainment of Measles during a Large Outbreak-Laboratory Compared to Epidemiological Confirmation

Measles is a highly contagious viral disease, and hence, sufficient herd immunity is obligatory to prevent infection transmission. Measles is still a cause of considerable disease burden globally, mainly in children. During a national measles outbreak in Israel in 2018-2019, the peak incidence rates occurred in the Jerusalem district. Most measles cases in the Jerusalem district (75.5%, 1702) were observed in children younger than 15 years of age, 49.2% (1109) were in children under 5 years of age, and 18.9% (425) were in infants under 1 year of age. The routine measles vaccination schedule includes two doses at 1 and 6 years of age. Most cases (1828, 81.1%) were unvaccinated (zero measles vaccine doses). These cases comprised the 425 affected infants under 1 year of age, who were ineligible for vaccination, along with the 1403 children over 1 year of age, who were otherwise unvaccinated. This study aimed to describe the epidemiologic and laboratory features of this measles outbreak, and to investigate case ascertainment (laboratory confirmed compared to epidemiologically confirmed cases). The study population included 2254 measles cases notified during the period spanning June 2018 to May 2019 in the Jerusalem district (incidence rate 176 per 10,000 population). Of the 2254 cases, 716 (31.8%) were laboratory confirmed, and 1538 (68.2%) were confirmed as epidemiologically linked. Most laboratory confirmed cases (420, 58.7%) underwent real-time PCR tests. Serological tests (measles IgM and IgG) were used in 189 (26.4%) cases, and a combination of RT-PCR and serology was used in 107 (14.9%) cases. In a multivariate model analysis, the variables significantly associated (after adjustment) with higher odds for laboratory confirmation included month of disease onset (late), additional measles cases in the household (single case), place of medical treatment (hospital; either emergency department, or hospitalization) and vaccination status (at least one prior vaccine dose). The measles outbreak described demonstrates the urgency of addressing vaccination gaps with appropriate outbreak prevention programs. The road to measles elimination needs to be paved with robust public health infrastructure, excellent field epidemiology for outbreak surveillance, investigation, and control, and laboratory proficiency.

Health system barriers to timely routine measles vaccinations in rural southwest China: a qualitative study on the perspectives of township vaccination professionals and village doctors

OBJECTIVES

A well-functioning health system ensures timely routine measles vaccinations for age-appropriate children, minimising measles risk. However, there is limited knowledge about the impact of the performance of immunisation programmes in health systems on the timeliness of measles vaccination. This study aimed to identify health system barriers to timely routine measles vaccination in rural southwest China, integrating the perspectives of township vaccination professionals and village doctors.

DESIGN, SETTING AND PARTICIPANTS

Qualitative study among township vaccination professionals and village doctors in rural Guangxi, southwest China.

METHODS

20 focus group discussions (FGDs) at township level and 120 in-depth interviews (IDIs) at village level, based on a four-theme framework. We used convenience sampling to recruit 60 township vaccination professionals and 120 village doctors in 2015. Instruments used were a semistructured questionnaire and interview outlines. We collected township and village-level data focusing on themes of health resources allocation, pattern of vaccination services, management and supervision of vaccination services, and perceptions of vaccination policy. The FGDs and IDIs were audio-recorded and transcribed. Braun and Clarke's thematic analysis approach was adopted to synthesise findings into meaningful subthemes, narrative text and illustrative quotations.

RESULTS

The health system barriers to timely routine vaccinations were explored across four themes. Barriers in the health resources allocation theme comprised (1) inadequacy of vaccination-related human resources (eg, lack of township vaccination professionals and lack of young village doctors), and (2) incompatible and non-identical information system of vaccination services across regions. Barriers in the pattern of vaccination services theme included inflexible vaccination services models, for example, routine vaccination services being offered monthly on fixed vaccination days, limited numbers of vaccination days per month, vaccination days being set on non-local market days, vaccination days being clustered into a specific period and absence of formal vaccination appointments. Ineffective economic incentive mechanism was identified as a barrier in the management and supervision of vaccination services theme. Low-degree participation of village doctors in routine vaccination services was identified as a barrier in the perceptions of vaccination policy theme.

CONCLUSIONS

We encourage policymakers and stakeholders to apply these findings to improve the timeliness of routine vaccination. Barriers to timely routine vaccination include inadequate allocation of vaccination-related resources and inflexible vaccination service delivery models. Financial and non-financial incentives should be used to retain and recruit vaccination professionals and village doctors. Strengthening information systems with unified data standards enables cross-regional data exchange. Optimising immunisation services and rationalising vaccination days could eliminate health system barriers and improve vaccination timeliness in rural China.

Rubella Vaccine Uptake among Women of Childbearing Age in Healthcare Settings

BACKGROUND

Rubella is a contagious viral infection that occurs most often in children and young adults. Rubella is the leading vaccine-preventable cause of birth defects. Rubella infection in pregnant women may cause fetal death or congenital defects known as congenital rubella syndrome. There is no specific treatment for rubella, but the disease is preventable by vaccination with an efficacy of over 95%. Vaccination coverage is still below the recommended levels and many cases have occurred worldwide. The COVID-19 pandemic has had a negative impact on the immunization programs and the quality of disease surveillance worldwide. Operators of the healthcare setting are at increased risk of infection due to their work duties and should receive preventive vaccination or serologic protection to work in a healthcare setting.

AIMS

To evaluate the serological evidence of rubella IgG antibodies in female healthcare operators of childbearing age, to assess the risk of a breakthrough infection and the need for an additional dose of vaccine.

METHODS

We collected age and antibody titers from 449 young female operators aged <50 years who underwent the periodic surveillance at the Occupational Medicine Unit of the Policlinico Tor Vergata, Rome, from January to July 2022. Subjects were considered immune if the anti-rubella IgG titer was >11.00 IU/mL.

RESULTS

The rate of serologically unprotected subjects was 9.13% (41/449). The mean age of protected subjects was 26.93 years, while the mean age of unprotected subjects was 28.24 years. Age did not correlate with mean titer on statistical analysis (p = 0.10). The acceptance rate among unprotected operators was 31.7%. A positive attitude towards vaccination was found in 11/28 (39.3%) of the unvaccinated subjects, while a negative tendency was found in 2/28 (7.1%) of these subjects; most of the unvaccinated operators 15/28 (53.6%) prefer to postpone the administration of the vaccine. When compared with a similar population from the pre-pandemic period, the actual proportion of immune female subjects was not significantly different from that found in 2019 (90.87% vs. 90.3%).

CONCLUSIONS

Protection against rubella was suboptimal among female healthcare workers of childbearing age. Acceptance of the rubella vaccine among these operators was low. Most of those who were hesitant intended to postpone the vaccination, while a minority had negative attitudes toward vaccination. A policy of mandatory vaccination policy should overcome the reluctance of operators.

Immunogenicity and safety of Mebella™ vaccine developed by Human Biologicals Institute in a Phase II/III, randomized, multicentric, non-inferiority study

BACKGROUND

The goal of 'Measles and Rubella Strategic Framework 2021-2030' is to make "A world free from measles and rubella". To be a part of this journey, Human Biologicals Institute has developed Mebella™ vaccine, which is a lyophilized Measles and Rubella (Live) vaccine. A randomized, single blind, comparative, multicenter Phase II/III trial was conducted to compare the immunogenicity and safety of Mebella™ vaccine with MR-VAC® vaccine in healthy subjects.

METHODS

A total of 888 subjects were enrolled in four age groups (222 subjects in each group) of 18 years to 49 years; 2 years to below 18 years; 12 months to below 24 months; and 9 months to below 12 months of age. The subjects were randomized in 2:1 ratio to receive single dose of either Mebella™ vaccine of Human Biologicals Institute or MR-VAC® vaccine. Immunogenicity was assessed at 42 days after the vaccination and was compared between the vaccine arms in each group. Safety was also assessed and compared between the vaccine arms during the study period.

RESULTS

A total of 875 subjects completed the study out of 888 enrolled subjects. The seroprotection rates, seroconversion rates, and geometric mean titres for both Measles and Rubella components of Mebella™ vaccine were found to be comparable and non-inferior to the MR-VAC® vaccine after 42 days of vaccination. Injection site pain was the most common local adverse event reported whereas fever was the only systemic adverse event reported in both the vaccine arms. No serious adverse event was reported.

CONCLUSION

It was concluded from the study results that the test vaccine, Mebella™, was immunogenic and well tolerated and was non-inferior to the comparator vaccine, MR-VAC®, when administered to healthy subjects of 9 months to 49 years of age. Clinical Trial Registry of India Identifier: CTRI/2020/07/026930.

A next-generation intranasal trivalent MMS vaccine induces durable and broad protection against SARS-CoV-2 variants of concern

As SARS-CoV-2 variants of concern (VoCs) that evade immunity continue to emerge, next-generation adaptable COVID-19 vaccines which protect the respiratory tract and provide broader, more effective, and durable protection are urgently needed. Here, we have developed one such approach, a highly efficacious, intranasally delivered, trivalent measles-mumps-SARS-CoV-2 spike (S) protein (MMS) vaccine candidate that induces robust systemic and mucosal immunity with broad protection. This vaccine candidate is based on three components of the MMR vaccine, a measles virus Edmonston and the two mumps virus strains [Jeryl Lynn 1 (JL1) and JL2] that are known to provide safe, effective, and long-lasting protective immunity. The six proline-stabilized prefusion S protein (preS-6P) genes for ancestral SARS-CoV-2 WA1 and two important SARS-CoV-2 VoCs (Delta and Omicron BA.1) were each inserted into one of these three viruses which were then combined into a trivalent "MMS" candidate vaccine. Intranasal immunization of MMS in IFNAR1-/- mice induced a strong SARS-CoV-2-specific serum IgG response, cross-variant neutralizing antibodies, mucosal IgA, and systemic and tissue-resident T cells. Immunization of golden Syrian hamsters with MMS vaccine induced similarly high levels of antibodies that efficiently neutralized SARS-CoV-2 VoCs and provided broad and complete protection against challenge with any of these VoCs. This MMS vaccine is an efficacious, broadly protective next-generation COVID-19 vaccine candidate, which is readily adaptable to new variants, built on a platform with a 50-y safety record that also protects against measles and mumps.

[Respiratory infections: Additional transmission-based precautions in healthcare facilities]

INTRODUCTION

In health care, measures against cross-transmission of microorganisms are codified by standard precautions, and if necessary, they are supplemented by additional precautions.

STATE OF THE ART

Several factors impact transmission of microorganisms via the respiratory route: size and quantity of the emitted particles, environmental conditions, nature and pathogenicity of the microorganisms, and degree of host receptivity. While some microorganisms necessitate additional airborne or droplet precautions, others do not.

PROSPECTS

For most microorganisms, transmission patterns are well-understood and transmission-based precautions are well-established. For others, measures to prevent cross-transmission in healthcare facilities remain under discussion.

CONCLUSIONS

Standard precautions are essential to the prevention of microorganism transmission. Understanding of the modalities of microorganism transmission is essential to implementation of additional transmission-based precautions, particularly in view of opting for appropriate respiratory protection.

Using multi-tissue transcriptome-wide association study to identify candidate susceptibility genes for respiratory infectious diseases

Objective: We explore the candidate susceptibility genes for influenza A virus (IAV), measles, rubella, and mumps and their underlying biological mechanisms.

Methods: We downloaded the genome-wide association study summary data of four virus-specific immunoglobulin G (IgG) level data sets (anti-IAV IgG, anti-measles IgG, anti-rubella IgG, and anti-mumps virus IgG levels) and integrated them with reference models of three potential tissues from the Genotype-Tissue Expression (GTEx) project, namely, whole blood, lung, and transformed fibroblast cells, to identify genes whose expression is predicted to be associated with IAV, measles, mumps, and rubella.

Results: We identified 19 significant genes (ULK4, AC010132.11, SURF1, NIPAL2, TRAP1, TAF1C, AC000078.5, RP4-639F20.1, RMDN2, ATP1B3, SRSF12, RP11-477D19.2, TFB1M, XXyac-YX65C7_A.2, TAF1C, PCGF2, and BNIP1) associated with IAV at a Bonferroni-corrected threshold of p &lt; 0.05; 14 significant genes (SOAT1, COLGALT2, AC021860.1, HCG11, METTL21B, MRPL10, GSTM4, PAQR6, RP11-617D20.1, SNX8, METTL21B, ANKRD27, CBWD2, and TSFM) associated with measles at a Bonferroni-corrected threshold of p &lt; 0.05; 15 significant genes (MTOR, LAMC1, TRIM38, U91328.21, POLR2J, SCRN2, Smpd4, UBN1, CNTROB, SCRN2, HOXB-AS1, SLC14A1, AC007566.10, AC093668.2, and CPD) associated with mumps at a Bonferroni-corrected threshold of p &lt; 0.05; and 13 significant genes (JAGN1, RRP12, RP11-452K12.7, CASP7, AP3S2, IL17RC, FAM86HP, AMACR, RRP12, PPP2R1B, C11orf1, DLAT, and TMEM117) associated with rubella at a Bonferroni-corrected threshold of p &lt; 0.05.

Conclusions: We have identified several candidate genes for IAV, measles, mumps, and rubella in multiple tissues. Our research may further our understanding of the pathogenesis of infectious respiratory diseases.

Social clustering of unvaccinated children in schools in the Netherlands

For the measles-mumps-rubella (MMR) vaccine, the World Health Organization-recommended coverage for herd protection is 95% for measles and 80% for rubella and mumps. However, a national vaccine coverage does not reflect social clustering of unvaccinated children, e.g. in schools of Orthodox Protestant or Anthroposophic identity in The Netherlands. To fully characterise this clustering, we estimated one-dose MMR vaccination coverages at all schools in the Netherlands. By combining postcode catchment areas of schools and school feeder data, each child in the Netherlands was characterised by residential postcode, primary and secondary school (referred to as school career). Postcode-level vaccination data were used to estimate vaccination coverages per school career. These were translated to coverages per school, stratified by school identity. Most schools had vaccine coverages over 99%, but major exceptions were Orthodox Protestant schools (63% in primary and 58% in secondary schools) and Anthroposophic schools (67% and 78%). School-level vaccine coverage estimates reveal strong clustering of unvaccinated children. The school feeder data reveal strongly connected Orthodox Protestant and Anthroposophic communities, but separated from one another. This suggests that even at a national one-dose MMR coverage of 97.5%, thousands of children per cohort are not protected by herd immunity.

A highly efficacious live attenuated mumps virus-based SARS-CoV-2 vaccine candidate expressing a six-proline stabilized prefusion spike

With the rapid increase in SARS-CoV-2 cases in children, a safe and effective vaccine for this population is urgently needed. The MMR (measles/mumps/rubella) vaccine has been one of the safest and most effective human vaccines used in infants and children since the 1960s. Here, we developed live attenuated recombinant mumps virus (rMuV)-based SARS-CoV-2 vaccine candidates using the MuV Jeryl Lynn (JL2) vaccine strain backbone. The soluble prefusion SARS-CoV-2 spike protein (preS) gene, stablized by two prolines (preS-2P) or six prolines (preS-6P), was inserted into the MuV genome at the P-M or F-SH gene junctions in the MuV genome. preS-6P was more efficiently expressed than preS-2P, and preS-6P expression from the P-M gene junction was more efficient than from the F-SH gene junction. In mice, the rMuV-preS-6P vaccine was more immunogenic than the rMuV-preS-2P vaccine, eliciting stronger neutralizing antibodies and mucosal immunity. Sera raised in response to the rMuV-preS-6P vaccine neutralized SARS-CoV-2 variants of concern, including the Delta variant equivalently. Intranasal and/or subcutaneous immunization of IFNAR1-/- mice and golden Syrian hamsters with the rMuV-preS-6P vaccine induced high levels of neutralizing antibodies, mucosal immunoglobulin A antibody, and T cell immune responses, and were completely protected from challenge by both SARS-CoV-2 USA-WA1/2020 and Delta variants. Therefore, rMuV-preS-6P is a highly promising COVID-19 vaccine candidate, warranting further development as a tetravalent MMR vaccine, which may include protection against SARS-CoV-2.

An Epidemic Model with Pro and Anti-vaccine Groups

Here, an epidemiological model considering pro and anti-vaccination groups is proposed and analyzed. In this model, susceptible individuals can migrate between these two groups due to the influence of false and true news about safety and efficacy of vaccines. From this model, written as a set of three ordinary differential equations, analytical expressions for the disease-free steady state, the endemic steady state, and the basic reproduction number are derived. It is analytically shown that low vaccination rate and no influx to the pro-vaccination group have similar impacts on the long-term amount of infected individuals. Numerical simulations are performed with parameter values of the COVID-19 pandemic to illustrate the analytical results. The possible relevance of this work is discussed from a public health perspective.

Updates on Measles Incidence and Eradication: Emphasis on the Immunological Aspects of Measles Infection

Measles is an RNA virus infectious disease mainly seen in children. Despite the availability of an effective vaccine against measles, it remains a health issue in children. Although it is a self-limiting disease, it becomes severe in undernourished and immune-compromised individuals. Measles infection is associated with secondary infections by opportunistic bacteria due to the immunosuppressive effects of the measles virus. Recent reports highlight that measles infection erases the already existing immune memory of various pathogens. This review covers the incidence, pathogenesis, measles variants, clinical presentations, secondary infections, elimination of measles virus on a global scale, and especially the immune responses related to measles infection.