Antibody persistence in children aged 6–7 years one year following booster immunization with two MMR vaccines applied by aerosol or by injection

Measles in Czech population with varying vaccination rates in 2018-2019: clinical and laboratory differences between vaccinated and unvaccinated individuals and their relevance to clinical practice

BACKGROUND AND OBJECTIVES

In a highly vaccinated population, an increasing number of previously vaccinated measles cases can be expected. The aim of this study was to assess the effect of vaccination on the clinical course and immune response in relation to the current measles case definition.

METHODS

The presence of fever, catarrhal symptoms, exanthema and complications, and specific IgM and IgG positivity were assessed in all 230 patients and compared in 193 patients with known vaccination status, divided into measles-containing vaccine (MCV) groups: MCV0 (85 patients), MCV1 (25 patients) and MCV2 (83 patients).

RESULTS

Statistically significant differences between groups were found for catarrhal symptoms. Conjunctivitis and rhinitis were significantly less frequent in the MCV2 group (47% and 54%) compared to MCV0 (80% and 80%), p < 0.001 and p = 0.002 respectively. Typical exanthema was present in 74 (87%) MCV0 and 56 (67%) MCV2 patients, p = 0.005. Complications were most common in the MCV0 group (29%). ECDC clinical case criteria were met in 81 (95%) MCV0, 18 (72%) MCV1 and 59 (71%) MCV2 patients, p < 0.001. IgM were positive in 64 (83%) MCV0, 14 (74%) MCV1 and 36 (67%) MCV2 patients, differences were not statistically significant. There were highly significant differences in IgG between MCV0 and both vaccinated groups (p < 0.001).

CONCLUSIONS

A redefinition of the clinical case classification is essential to better capture modified measles and to raise awareness among healthcare workers of the differences in measles in vaccinated patients.

Prevention of measles, mumps and rubella: 40 years of global experience with M-M-RII

Measles, mumps, and rubella are highly contagious diseases that caused significant global mortality and morbidity in the pre-vaccine era. Since its first approval in the United States over 40 years ago, M-M-R_II has been used in >75 countries for prevention of these diseases. The vaccine has been part of immunization programs that have achieved dramatic global reductions in case numbers and mortality rates, as well as the elimination of measles and rubella in several countries and regions. This report summarizes over four decades of global safety, immunogenicity, efficacy, and effectiveness data for the vaccine. We include studies on the use of M-M-R_II in different age groups, concomitant use with other routine childhood vaccines, administration via different routes, persistence of immunity, and vaccine effectiveness during outbreaks of measles and mumps. We conclude that M-M-R_II is well tolerated and has shown consistently high performance during routine use in multiple countries, in randomized controlled trials with diverse designs, and in outbreak settings, including use as measles postexposure prophylaxis. Physicians, parents, and the public can continue to have a high degree of confidence in the use of M-M-R_II as a vital part of global public health programs.

Inhaled vaccine delivery in the combat against respiratory viruses: a 2021 overview of recent developments and implications for COVID-19

INTRODUCTION

As underlined by the late 2019 outbreak of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), vaccination remains the cornerstone of global health-care. Although vaccines for SARS-CoV-2 are being developed at a record-breaking pace, the majority of those that are licensed or currently registered in clinical trials are formulated as an injectable product, requiring a tightly regulated cold-chain infrastructure, and primarily inducing systemic immune responses.

AREAS COVERED

Here, we shed light on the status of inhaled vaccines against viral pathogens, providing background to the role of the mucosal immune system and elucidating what factors determine an inhalable vaccine's efficacy. We also discuss whether the development of an inhalable powder vaccine formulation against SARS-CoV-2 could be feasible. The review was conducted using relevant studies from PubMed, Web of Science and Google Scholar.

EXPERT OPINION

We believe that the scope of vaccine research should be broadened toward inhalable dry powder formulations since dry vaccines bear several advantages. Firstly, their dry state can tremendously increase vaccine stability and shelf-life. Secondly, they can be inhaled using disposable inhalers, omitting the need for trained health-care personnel and, therefore, facilitating mass-vaccination campaigns. Thirdly, inhalable vaccines may provide improved protection since they can induce an IgA-mediated mucosal immune response.

Use of M-M-R II outside of the routinely recommended age range - a systematic literature review

M-M-R®_II (M-M-R II) is routinely used in many countries at 12–15 months with a second dose at 4 to 6 years of age. However, the vaccine may need to be administered at other ages due to delays in the immunization schedule or in certain situations such as outbreaks or international travel. A systematic literature review was conducted to evaluate efficacy, immunogenicity and safety of M-M-R II among 6- to 11-month-olds and persons ≥7 years of age. A search for randomized controlled trials (RCTs) was conducted in 2019 including Medline, Embase and Cochrane CENTRAL. Only one study reported seroconversion rates after one dose in infants at 9 months of age: 87.4% (measles), 92.3% (mumps), and 91.2% (rubella); no safety data were reported. Seven studies reported immunogenicity and safety data for M-M-R II at ≥7 years of age. Seroconversion rates ranged from 96%-100% (measles), 65%-100% (mumps), and 91%-100% (rubella). Rates of selected adverse events ranged from 5.2%-8.7% for fever (≥38°C or ≥38.1°C), 2%-33.3% for injection site reactions, and 0.4% for measles/rubella-like rash (one study). No efficacy studies were found. This literature review identified RCTs with evidence to support that M-M-R II is immunogenic and well tolerated in individuals ≥7 years of age.

Immunogenicity, duration of protection, effectiveness and safety of rubella containing vaccines: A systematic literature review and meta-analysis

BACKGROUND

Rubella containing vaccines (RCV) prevent rubella virus infection and subsequent congenital rubella syndrome (CRS). To update the evidence on immunogenicity, duration of protection, effectiveness and safety of RCV, we conducted a systematic literature review.

METHODS

We searched EMBASE and SCOPUS, using keywords for rubella vaccine in combination with immunogenicity (seroconversion and seropositivity), duration of protection, efficacy/effectiveness, and safety. Original research papers involving at least one dose of RCV (at any age), published between 1-1-2010 and 17-5-2019 were included. Where appropriate, meta-analyses were performed. Quality of included studies was assessed using GRADE methodology.

RESULTS

We included 36 papers (32 randomized controlled trials (RCTs) and 4 observational studies) on immunogenicity (RA27/3 strain) in children and adolescent girls, 14 papers (5 RCTs and 9 observational studies) on duration of protection, one paper on vaccine effectiveness (VE) (BRDII strain), and 74 studies on safety, including three on safety in pregnancy. Meta-analysis of immunogenicity data showed 99% seroconversion (95% CI: 98-99%) after a single dose of RCV in children, independent of co-administration with other vaccines. Seroconversion after RCV1 below 9 months of age (BRDII strain, at 8 months) was 93% (95% CI: 92-95%). For duration of protection, the included studies showed a seropositivity of 88%-100% measured 1-20 years after one or two RCV doses. The single study on VE of BRDII strain, reported 100% VE after one and two doses. Among 34,332 individuals participating in the RCTs, 140 severe adverse events (SAEs) were reported as possibly related to RCV. Among the case reports on SAEs, the association with RCV was confirmed in one report (on fulminant encephalitis). Among 3,000 pregnant women who were inadvertently vaccinated, no SAEs were reported.

CONCLUSIONS

One and two doses of RCV are highly immunogenic for a long period of time, effective in preventing rubella and CRS, and safe.

High risk of mumps infection in children who received one dose of mumps-containing vaccine: waning immunity to mumps in children aged 2-5 years from kindergartens in Jiangsu Province, China

BACKGROUND

During the period of immunization with a single-dose measles-mumps-rubella (MMR) vaccine, which has been available since 2008in China, the incidence of mumps in children aged 2-5 years has been high. The aim of this study was to determine the immunity profile of mumps in children aged 2-5 years as part of the assessment of the MMR vaccination strategy.

METHODS

A cross-sectional survey of IgG antibodies against mumps virus in children aged 2-5 years was performed. Analysis by enzyme-linked immune sorbent assay(ELISA)was performed to measure IgG antibodies against mumps virus in the sera of 2-to5-year-old children who had been vaccinated with at least one dose of MMR vaccine.

RESULTS

Mumps outbreaks mainly occurred in kindergarten and primary schools and primarily involved children in kindergarten from 2015-2016 in Jiangsu Province. In total, 4,033 children were surveyed. The overall seroprevalence of mumps antibodies was 79.0% (95% CI:78.4-79.6), and the geometric mean concentration (GMC) was 323.6 mIU/ml (309.0-338.8). Both univariate and multivariate survival analysis of seroprevalence showed that several factors contributed to having significant seroprevalence among the 2-to-5-year-old group (P < .05). The seroprevalence of children with a single-dose MMR vaccine regimen (78.4%, 95% CI: 77.8-80.4) was significantly lower than that of children with a two-dose MMR vaccine regimen (96.5%, 95% CI: 88.6%-96.1%). The seroprevalence rate was negatively correlated with time since inoculation (P < .01).

CONCLUSION

Children who received a single dose of MMR vaccine in kindergarten, particularly the 2-year-old group in the northern region of Jiangsu Province, China, are at high risk of mumps infection. Our study demonstrates thata single-dose MMR vaccine regimen has a limited effect on controlling mumps, which highlights the benefit of introducing a two-dose MMR vaccine schedule.

Comparison of Immunogenicity and Protective Efficacy of PPR Live Attenuated Vaccines (Nigeria 75/1 and Sungri 96) Administered by Intranasal and Subcutaneous Routes

Following the successful eradication of rinderpest, the World Organization of Animal Health (OIE) and the Food and Agriculture Organization (FAO) have set a goal to eradicate peste des petits ruminants (PPR) globally by 2030. Vaccination is being taken forward as the key strategy along with epidemiological surveillance to target vaccination efforts and eradicate the disease. PPR is highly contagious and is generally spread by aerosolized droplets and close contact. Currently, two live attenuated vaccines (Nigeria 75/1 and Sungri 96) are in use, and administered subcutaneously to prevent transmission of PPR and protect vaccinated animals. Though the target cells that support primary replication of PPR vaccine strains are largely unknown, it is hypothesized that the immune response could be intensified following intranasal vaccine delivery as this route mimics the natural route of infection. This study aims to compare the immunogenicity and protective efficacy of the two currently available live attenuated PPR vaccines following subcutaneous and intranasal routes of vaccination in target species. Groups of five goats were vaccinated with live attenuated PPR vaccines (Nigeria 75/1 and Sungri 96) by either the subcutaneous or intranasal route, and 28 days later challenged intranasally with virulent PPR virus. All vaccinated animals regardless of vaccination route produced PPRV-specific antibodies post-vaccination. Following challenge, all goats were protected from clinical disease, and vaccination was considered to have induced sterilizing immunity. This study demonstrates that the intranasal route of vaccination is as effective as the subcutaneous route of vaccination when using available live attenuated PPR vaccines.

Application of a mixture model to assess the effect of measles-mumps-rubella vaccine on the mumps epidemic in children from kindergarten to early school age in Jiangsu Province, China

A single dose of the measles-mumps-rubella (MMR) vaccine has been applied in routine immunizations for children in China; however, the Immunoglobulin G (IgG) antibody level of mumps in children from kindergarten to early school age with MMR vaccine immunization history has not been elucidated. This study aimed to describe the immunity profile of children from kindergarten to early school age to identify the susceptible population. In Jiangsu Province, a cross-sectional survey of 4- to 8-year-old children who were vaccinated with at least one dose of MMR vaccine was conducted. IgG antibody results were analyzed by employing both the Enzyme-Linked Immunosorbent Assay (ELISA) cutoff values and the mixture model. A total of 7436 eligible subjects were enrolled: 3386 subjects were in kindergarten, and 4450 were in primary school. The overall seroprevalence (75.4%, 95% CI: 74.4%-76.4%) and Geometric mean concentration (GMC, 201.4U/ml, 95% CI: 194.1-209.4) of mumps antibodies in 2016 were low. The seroprevalence of children in kindergarten (78.1%, 95% CI: 76.6%-79.4%) was significantly higher than that of children in primary school (73.2%, 95% CI: 71.2%-74.6%). The GMC was negatively correlated with the time of inoculation (F = 32.17, P = 0.002). The mixture model enables a more comprehensive understanding of serological results by investigating four levels of antibody response, suggesting that there is a small fraction of the population with waning immunity. Children in kindergarten and primary school whom had received one dose of MMR vaccine were at a higher risk of mumps infection, particularly the 7-year-old group in the central region. Therefore, the single-dose MMR vaccine schedule has a limited impact on mumps control and prevention, and a two-dose MMR vaccine schedule should be introduced.