Immunity to mumps before and after MMR vaccination at 12 years of age in the first generation offered the two-dose immunization programme

Mumps serological surveillance following 10 years of a one-dose mumps-containing-vaccine policy in Fujian Province, China

BACKGROUND

Since 2008, Fujian province provided measles-rubella (MR) vaccine at 8 months followed by measles-mumps-rubella (MMR) vaccine at 18 months a one-dose mumps-containing-vaccine (MuCV) schedule. Several mumps outbreaks have occurred recently in Fujian. Serological surveillance can assess population immunity to mumps and identify risk factors for mumps.

METHODS

We conducted a cross-sectional serosurvey of mumps IgG antibodies in the general population of Fujian Province in 2018 and compare results with a similar study conducted in 2009, when the routine schedule had no MuCV. We analyzed changes in mumps epidemiology after implementation of a one-dose MuCV vaccination strategy.

RESULTS

Mumps seroprevalence was 78.6% (95% CI: 77.4-79.8), and the geometric mean concentration (GMC) of mumps antibodies was 245.8 IU/ml (95% CI:237.3-255.1). MuCV vaccination at 18 months resulted in increased seroprevalence and GMCs. Seroprevalence and GMCs varied by age, gender, and number of doses received. Except for children under 18 months, seroprevalence and GMCs were lowest among 10-15-year-olds. Each year after introduction of the one-dose MuCV vaccination policy, the highest incidence of mumps was among 4-6-year-olds and 9-15-year-olds, gradually shifting to older age groups.

CONCLUSION

A one-dose mumps-containing vaccine schedule does not provide sustained and stable mumps immunity in Fujian. To reduce the risk of mumps, we recommend supplementary vaccination of children without a history of receiving at least one MuCV dose or who are seronegative at 10-15 years of age.

Mumps Outbreaks in Vaccinated Populations-Is It Time to Re-assess the Clinical Efficacy of Vaccines?

History illustrates the remarkable public health impact of mass vaccination, by dramatically improving life expectancy and reducing the burden of infectious diseases and co-morbidities worldwide. It has been perceived that if an individual adhered to the MMR vaccine schedule that immunity to mumps virus (MuV) would be lifelong. Recent mumps outbreaks in individuals who had received two doses of the Measles Mumps Rubella (MMR) vaccine has challenged the efficacy of the MMR vaccine. However, clinical symptoms, complications, viral shedding and transmission associated with mumps infection has been shown to be reduced in vaccinated individuals, demonstrating a benefit of this vaccine. Therefore, the question of what constitutes a good mumps vaccine and how its impact is assessed in this modern era remains to be addressed. Epidemiology of the individuals most affected by the outbreaks (predominantly young adults) and variance in the circulating MuV genotype have been well-described alluding to a collection of influences such as vaccine hesitancy, heterogeneous vaccine uptake, primary, and/or secondary vaccine failures. This review aims to discuss in detail the interplay of factors thought to be contributing to the current mumps outbreaks seen in highly vaccinated populations. In addition, how mumps diagnoses has progressed and impacted the understanding of mumps infection since a mumps vaccine was first developed, the limitations of current laboratory tests in confirming protection in vaccinated individuals and how vaccine effectiveness is quantified are also considered. By highlighting knowledge gaps within this area, this state-of-the-art review proposes a change of perspective regarding the impact of a vaccine in a highly vaccinated population from a clinical, diagnostic and public perspective, highlighting a need for a paradigm shift on what is considered vaccine immunity.

Current Status of Mumps Virus Infection: Epidemiology, Pathogenesis, and Vaccine

Mumps is an important childhood infectious disease caused by mumps virus (MuV). We reviewed the epidemiology, pathogenesis, and vaccine development of mumps. Previous studies were identified using the key words “mumps” and “epidemiology”, “pathogenesis” or “vaccine” in MEDLINE, PubMed, Embase, Web of Science, and Google Scholar. We excluded the articles that were not published in the English language, manuscripts without abstracts, and opinion articles from the review. The number of cases caused by MuV decreased steeply after the introduction of the mumps vaccine worldwide. In recent years, a global resurgence of mumps cases in developed countries and cases of aseptic meningitis caused by some mumps vaccine strains have renewed the importance of MuV infection worldwide. The performance of mumps vaccination has become an important issue for controlling mumps infections. Vaccine development and routine vaccination are still effective measures to globally reduce the incidence of mumps infections. During outbreaks, a third of MMR vaccine is recommended for groups of persons determined by public authorities.

Waning Immunity and Microbial Vaccines-Workshop of the National Institute of Allergy and Infectious Diseases

Since the middle of the 20th century, vaccines have made a significant public health impact by controlling infectious diseases globally. Although long-term protection has been achieved with some vaccines, immunity wanes over time with others, resulting in outbreaks or epidemics of infectious diseases. Long-term protection against infectious agents that have a complex life cycle and antigenic variation remains a key challenge. Novel strategies to characterize the short- and long-term immune responses to vaccines and to induce immune responses that mimic natural infection have recently emerged. New technologies and approaches in vaccinology, such as adjuvants, delivery systems, and antigen formulations, have the potential to elicit more durable protection and fewer adverse reactions; together with in vitro systems, these technologies have the capacity to model and accelerate vaccine development. The National Institute of Allergy and Infectious Diseases (NIAID) held a workshop on 19 September 2016 that focused on waning immunity to selected vaccines (for Bordetella pertussis, Salmonella enterica serovar Typhi, Neisseria meningitidis, influenza, mumps, and malaria), with an emphasis on identifying knowledge gaps, future research needs, and how this information can inform development of more effective vaccines for infectious diseases.

Assessing mumps outbreak risk in highly vaccinated populations using spatial seroprevalence data

Mumps is a potentially severe viral infection. The incidence of mumps has declined dramatically in high-income countries since the introduction of mumps antigen-containing vaccines. However, recent large outbreaks of mumps in highly vaccinated populations suggest waning of vaccine-induced immunity and primary vaccine failure. In this paper we present a simple method for identifying geographic regions with high outbreak potential, demonstrated using 2006 mumps seroprevalence data from Belgium and Belgian vaccination coverage data. Predictions of the outbreak potential in terms of the effective reproduction number in future years signal an increased risk of new mumps outbreaks. Literature reviews on serological information for both primary vaccine failure and waning immunity provide essential information for our predictions. Tailor-made additional vaccination campaigns would be valuable for decreasing local pockets of susceptibility, thereby reducing the risk of future large-scale mumps outbreaks.

Mumps outbreak in the Republic of Moldova, 2007-2008

BACKGROUND

Moldova experienced a nationwide mumps outbreak between 2007 and 2008. Single-dose monovalent mumps vaccination at 15 to 18 months was introduced in 1983, replaced by a 2-dose MMR schedule at age 1 and 6 to 7 years in 2002. We investigated the outbreak to quantify its extent, explore the role of primary and secondary vaccine failure, and provide control recommendations.

METHODS

We analyzed national mumps surveillance and vaccination coverage data to estimate vaccine effectiveness (VE) using the screening method. A retrospective cohort study in 5 educational institutions was conducted to determine age-specific attack rates (ARs) and VE. We compared vaccine strain-specific ARs. Isolation and genotyping of mumps virus strains were performed.

RESULTS

Of 31,142 cases reported during October 2007 and July 2008, 80% were in 15- to 24-year-olds. Of cases with information (66%), 92% were vaccinated once, 4% twice. One-dose mumps VE estimates based on surveillance data over 1997-2001 declined from 91% (95% CI: 88%-92%) in 2-year-olds to 72% (70%-74%) in 15- to 19-year-olds. In the cohort study (n = 1589), VE was -40% (-120% to 20%) for 1 dose. For 2 doses it was 62% (-43% to 90%) in 13- to 15-year-olds. ARs were higher in individuals vaccinated with Urabe strains (43%) than with Leningrad-Zagreb strains (14%, P < 0.001). Mumps virus genotype G5 was identified.

CONCLUSIONS

Low effectiveness of single-dose mumps vaccination was the main cause of the outbreak. Waning immunity may have contributed to this. The risk of mumps in 2-dose vaccinees was low. Other countries in which large population groups have received <2 doses of mumps vaccine may face similar outbreaks.

Epidemiologic and diagnostic evaluation of a recent mumps outbreak using oral fluid samples

OBJECTIVE

To determine the optimal strategy to investigate mumps virus infection in a partially vaccinated cohort.

STUDY DESIGN

122 oral fluid and serum samples were collected in a recent outbreak in Ireland. The largest age cohort, students aged 18-21 years old attending third level institutions, were investigated using virus isolation, detection of mumps specific IgM, IgG, RT-PCR and molecular genotyping.

RESULTS

97% of patients had both detectable serum IgM and IgG. Mumps virus RNA was detected in 17 oral fluid samples and 14 of these originated from a single geographic location. Only 6 of the IgM positive samples had detectable mumps virus RNA whereas this could be detected in 11 IgM negative samples. Genotyping studies revealed that genotypes G and J were co-circulating during this outbreak.

CONCLUSIONS

The use of an oral fluid sample to detect mumps virus RNA and IgM offers a major improvement over serological diagnosis in acute infection in both non-vaccinated or partially vaccinated individuals, and has the advantage that specimens are collected non-invasively.

Mumps

Mumps is a common childhood infection caused by the mumps virus. The hallmark of infection is swelling of the parotid gland. Aseptic meningitis and encephalitis are common complications of mumps together with orchitis and oophoritis, which can arise in adult men and women, respectively; other complications include deafness and pancreatitis. Clinical diagnosis can be based on the classic parotid swelling; however, this feature is not present in all cases of mumps and can also occur in various other disorders. Laboratory diagnosis is based on isolation of virus, detection of viral nucleic acid, or serological confirmation (generally presence of IgM mumps antibodies). Mumps is vaccine-preventable, and one dose of mumps vaccine is about 80% effective against the disease. Routine vaccination has proven highly effective in reducing the incidence of mumps, and is presently used by most developed countries; however, there have been outbreaks of disease in vaccinated populations. In 2005, a large epidemic peaked in the UK, and in 2006 the American midwest had several outbreaks. In both countries, the largest proportion of cases was in young adults. In the UK, susceptible cohorts too old to have been vaccinated and too young to have been exposed to natural infections were the primary cause of the mumps epidemic. In the USA, effectiveness and uptake in combination appear not to have been sufficient to obtain herd immunity for mumps in populations such as college students.

Backward bifurcations and multiple equilibria in epidemic models with structured immunity

Many disease pathogens stimulate immunity in their hosts, which then wanes over time. To better understand the impact of this immunity on epidemiological dynamics, we propose an epidemic model structured according to immunity level that can be applied in many different settings. Under biologically realistic hypotheses, we find that immunity alone never creates a backward bifurcation of the disease-free steady state. This does not rule out the possibility of multiple stable equilibria, but we provide two sufficient conditions for the uniqueness of the endemic equilibrium, and show that these conditions ensure uniqueness in several common special cases. Our results indicate that the within-host dynamics of immunity can, in principle, have important consequences for population-level dynamics, but also suggest that this would require strong non-monotone effects in the immune response to infection. Neutralizing antibody titer data for measles are used to demonstrate the biological application of our theory.

Vaccine effectiveness estimates, 2004-2005 mumps outbreak, England

As vaccinated children approach adolescence, immunity wanes, which may contribute to outbreaks.

The United Kingdom and United States have recently experienced large outbreaks of mumps, which raises concerns about vaccine effectiveness. The effectiveness of the mumps component of the measles, mumps, rubella (MMR) vaccine was estimated using the screening method. In England from January 2004 through March 2005, 312 cases of mumps were reported in children eligible to have received 2 doses of MMR vaccine. Of these children, 52 (16.7%) had received 1 dose of MMR vaccine, and 97 (31.1%) had received 2 doses. Vaccine effectiveness was 88% (95% confidence interval [CI] 83%–91%) for 1 dose and 95% (95% CI 93%–96%) for 2 doses. The effectiveness of 1 dose declined from 96% (95% CI 81%–99%) in 2-year-olds to 66% (95% CI 30%–83%) in 11- to 12-year-olds, and the effectiveness of 2 doses declined from 99% (95% CI 97%–99.5%) in 5- to 6-year-olds to 86% (95% CI 74%–93%) in 11- to 12-year-olds (p<0.001 for 1 or 2 doses). Waning immunity may contribute to mumps outbreaks in older vaccinated populations.

Silencing T cells or T-cell silencing: concepts in virus-induced immunosuppression

The ability to evade or suppress the host's immune response is a property of many viruses, indicating that this provides an advantage for the pathogen to spread efficiently or even to establish a persistent infection. The type and complexity of its genome and cell tropism but also its preferred type of host interaction are important parameters which define the strategy of a given virus to modulate the immune system in an optimal manner. Because they take a central position in any antiviral defence, the activation and function of T cells are the predominant target of many viral immunosuppressive regimens. In this review, two different strategies whereby this could be achieved are summarized. Retroviruses can infect professional antigen-presenting cells and impair their maturation and functional properties. This coincides with differentiation and expansion of silencing T cells referred to as regulatory T cells with suppressive activity, mainly to CD8+ effector T cells. The second concept, outlined for measles virus, is a direct, contact-mediated silencing of T cells which acquire a transient paralytic state.

Increasing incidence of mumps in Scotland: options for reducing transmission

BACKGROUND

There has been a dramatic increase in mumps in Scotland since November 2003, with cases primarily in adolescents and young adults.

OBJECTIVES

This paper describes mumps epidemiology in Scotland, undertakes a risk assessment and considers option for reducing transmission.

RESULTS

Mumps is primarily a risk for the 13-25 year age group, as they have neither been offered two routine doses of measles, mumps and rubella MMR vaccine, nor been exposed to wild virus. Transmission is facilitated by a high degree of social mixing, with enclosed settings (school, universities etc.) being higher risk. On the basis of susceptibility and risk of transmission, three categories of higher (17-20 years), intermediate (21-22; 15-16 years), and low (23-25; 13-14 years) risk were defined, all in higher risk enclosed settings. Herd immunity would be very difficult to achieve, as it would require unrealistically high MMR uptake (an additional 45-80% in 17-20 year olds). A risk management strategy of reducing transmission and decreasing the likelihood of outbreaks was therefore proposed. Action would be targeted at the higher risk group (17-20 years) in higher risk settings. Three options were considered: do nothing; opportunistic immunisation through GPs; a mass campaign. The 'do nothing' option was discounted. The preferred option was to alert GPs to the need to offer MMR vaccine to 17-20 year olds in higher risk settings. The rationale for this was that it had the lowest cost, avoided disruption to services, and primarily that it would reduce the probability of mumps transmission in higher risk settings.

CONCLUSIONS

The Chief Medical Officer issued a letter to all health professionals in Scotland encouraging them to offer MMR vaccine to 13-15 year olds, who had not previously received two doses, and particularly those aged 17-20 years in higher risk settings.

Immunogenicity of second dose measles-mumps-rubella (MMR) vaccine and implications for serosurveillance

Measles and mumps, but not rubella, outbreaks have been reported amongst populations highly vaccinated with a single dose of measles-mumps-rubella (MMR) vaccine. Repeated experience has shown that a two-dose regime of measles vaccine is required to eliminate measles. This paper reports the effect of the first and second MMR doses on specific antibody levels in a variety of populations.2-4 years after receiving a first dose of MMR vaccine at age 12-18 months, it was found that a large proportion of pre-school children had measles (19.5%) and mumps (23.4%) IgG antibody below the putative level of protection. Only a small proportion (4.6%) had rubella antibody below the putative protective level. A total of 41% had negative or equivocal levels to one or more antigens. The proportion measles antibody negative (but not rubella or mumps) was significantly higher in children vaccinated at 12 months of age than at 13-17 months. There was no evidence for correlation of seropositivity to each antigen, other than that produced by a small excess of children (1%) negative to all three antigens. After a second dose of MMR, the proportion negative to one or more antigens dropped to <4%. Examination of national serosurveillance data, found that following an MR vaccine campaign in cohorts that previously received MMR, both measles and rubella antibody levels were initially boosted but declined to pre-vaccination levels within 3 years. Our study supports the policy of administering a second dose of MMR vaccine to all children. However, continued monitoring of long-term population protection will be required and this study suggests that in highly vaccinated populations, total measles (and rubella) IgG antibody levels may not be an accurate reflection of protection. Further studies including qualitative measures, such as avidity, in different populations are merited and may contribute to the understanding of MMR population protection.

Mumps virus neutralizing antibodies do not protect against reinfection with a heterologous mumps virus genotype

In April 1999, a previously healthy 22-year-old woman was taken ill with fever and bilateral swelling of the parotid glands. A chronic course of disease extending from April to December was found with swelling of the parotid glands, fatigue, low grade fever, episodes of tachycardia and nightswetting. Mumps virus RNA of genotype A character based on the SH (small hydrophobic) protein gene classification was demonstrated in three serum samples collected during the course of clinical disease. Different criteria for reinfection were fulfilled including demonstration of IgG antibodies by ELISA in a preinfection serum sample. The preinfection serum sample of the patient was able to efficiently neutralize the infectivity of a heterologous genotype D strain but was unable to neutralize the homologous genotype A virus. The findings in the present study may offer an explanation of a mechanism behind previously observed vaccine failures and the occurrence of reinfection with heterologous mumps virus strains.

Immune response after primary and re-vaccination with different combined vaccines against measles, mumps, rubella

The humoral immune response after primary and re-vaccination confirmed the high immunogenicity of the combined vaccines used: "MMR-Vax(R)", "Pluserix(R)" and "Triviraten(R)". The investigation of paired serum samples of prevaccinal seronegative infants (n90-100% for all three components with the exception of the mumps component of "Triviraten(R)" (38%). However, by additional methods (plaque neutralisation test, immunofluorescence test) mumps antibodies could be detected in 93.4% of infants having received vaccine "Triviraten(R)". The mean values of antibody activities against the three components did not differ significantly after vaccination with "MMR-Vax(R)" and "Pluserix(R)". However, after vaccination with "Triviraten(R)" the mean antibody values were significantly lower (P<0.01) against the measles strain "Edmonston-Zagreb" and especially lower (2-20 times) against the mumps virus strain "Rubini". Revaccination of pre-vaccinal seropositive schoolchildren and adolescents (n=676) with "MMR-Vax(R)" and "Pluserix(R)" produced no different results. The rate of vaccinees responding with a booster reaction reached 68.4% for measles and mumps, but only 8.6% for rubella. A booster reaction could be observed in 100% of those vaccinees who had antibodies at a low level, also in the case of naturally acquired immunity. The low-level range for antibodies against measles was defined as 0.15<0. 40 IU/ml, mumps 1:230</=1:500 and rubella 7-16 IU/ml. The rate of vaccinees with low-level antibodies against measles can become as high as 10%, for mumps 20% and for rubella 3%. The correlation between the level of antibodies and protection against the disease is discussed. The rate of individuals in a population with doubtful protection (unvaccinated, non-responder and low responder after primary vaccination) prevents to reach the herd immunity of 95% necessary for elimination. The results of our serological studies strongly recommend re-vaccination against measles, mumps and rubella.

Response to measles revaccination among toddlers in Saudi Arabia by the use of two different trivalent measles-mumps-rubella vaccines

This trial confirmed the immunogenicity of a standard dose of measles vaccine Edmonston-Zagreb strain administered at the age of 6 months as evaluated serologically at 12 months of age in 94 healthy children in Saudi Arabia. The residual seropositivity rate for measles was 53.4 and 80.6% as measured by enzyme immunoassay (EIA) and plaque neutralization, respectively, and could be increased to virtually 100% seroprotection after immunization with 1 of 2 measles-mumps-rubella (MMR) vaccines (Triviraten Berna or MMR II MSD) at 12 months of age. In both groups, more than 90% of infants showed an immune response to the mumps and rubella vaccine strains at 14 months of age. There was a difference in the geometric mean titres of mumps antibodies in favour of MMR II (P < 0.001). The seroconversion rates for mumps antibodies differed between the 2 vaccines because of the different test systems and/or the different cut-off levels used. The study reconfirmed that for the assessment of Rubini mumps vaccine-induced antibodies the indirect immunofluorescence test is superior to the EIA. The systemic tolerability of both vaccines was excellent. Triviraten Berna is exclusively propagated on human diploid cell cultures and hence free of avian proteins.