Vaccine effectiveness estimates, 2004-2005 mumps outbreak, England

An assessment of mumps vaccine effectiveness by dose during an outbreak in Canada

BACKGROUND

This investigation was done to assess vaccine effectiveness of one and two doses of the measles, mumps and rubella (MMR) vaccine during an outbreak of mumps in Ontario. The level of coverage required to reach herd immunity and interrupt community transmission of mumps was also estimated.

METHODS

Information on confirmed cases of mumps was retrieved from Ontario's integrated Public Health Information System. Cases that occurred between Sept. 1, 2009, and June 10, 2010, were included. Selected health units supplied coverage data from the Ontario Immunization Record Information System. Vaccine effectiveness by dose was calculated using the screening method. The basic reproductive number (R(0)) represents the average number of new infections per case in a fully susceptible population, and R(0) values of between 4 and 10 were considered for varying levels of vaccine effectiveness.

RESULTS

A total of 134 confirmed cases of mumps were identified. Information on receipt of MMR vaccine was available for 114 (85.1%) cases, of whom 63 (55.3%) reported having received only one dose of vaccine; 32 (28.1%) reported having received two doses. Vaccine effectiveness of one dose of the MMR vaccine ranged from 49.2% to 81.6%, whereas vaccine effectiveness of two doses ranged from 66.3% to 88.0%. If we assume vaccine effectiveness of 85% for two doses of the vaccine, vaccine coverage of 88.2% and 98.0% would be needed to interrupt community transmission of mumps if the corresponding reproductive values were four and six.

INTERPRETATION

Our estimates of vaccine effectiveness of one and two doses of mumps-containing vaccine were consistent with the estimates that have been reported in other outbreaks. Outbreaks occurring in Ontario and elsewhere serve as a warning against complacency over vaccination programs.

Reappraisal of MMR vaccines currently used in Korea

BACKGROUND

Although MMR vaccine is widely used in Korea, there are limited studies on the currently used vaccines. We evaluated the immunogenicity and safety of MMR vaccines in Korean children.

METHODS

For first and second dose immunization, children aged 12-23 months and 4-6 years were enrolled. All subjects received a single dose of either Priorix™ (Glaxo Smithkline Biologicals, Rixensart, Belgium) or MMRII® (Merck & Co., Inc., West Point, PA, USA). Pre- and postvaccine sera were collected from all participants. Antibody levels were determined by ELISA (Enzygnost®; Dade Behring, Schwalbach, Germany). Safety monitoring included local adverse events for 5 days and systemic adverse events for 42 days following vaccination.

RESULTS

One hundred twenty-one subjects were enrolled in the 12-23 months age group and 39 in the 4-6 years age group. The seroconversion rate in the 12-23 months age group was 97.9-100.0% for measles, 85.1-88.9% for mumps and 100.0% for rubella. All children 4-6 years of age previously seronegative showed seroconversion for measles, mumps and rubella. Local adverse events were reported in 8.3-16.1% (12-23 months age) and 27.8-31.6% (4-6 years age), and 40.0-48.2% (12-23 months age) and 42.1-61.1% (4-6 years age) experienced at least more than 1 systemic adverse reaction. No vaccine-related serious adverse events were reported. Among the same age groups, there was no significant difference in adverse events between the two vaccines.

CONCLUSION

The MMR vaccines are safe and show good immunogenic responses in children. These data will be invaluable when we introduce diverse vaccines in the following future.

Mumps outbreak in Israel's highly vaccinated society: are two doses enough?

Mumps outbreaks in recent years have given rise to questions about the effectiveness of the mumps vaccine. This study examined the epidemiological data from a recent mumps outbreak in Israel and from outbreaks in other countries with high vaccination coverage, and considered whether long-established vaccination policies designed to protect against mumps are in need of revision. Of over 5000 case patients in the Israeli outbreak, half of whom were in the Jerusalem health district, nearly 40% were aged ≥15 years and, of those whose vaccination status was known, 78% had been fully vaccinated for their age - features similar to those in recent mumps outbreaks in Europe and North America. The epidemiological and laboratory evidence suggests that many previously vaccinated adolescents and young adults are now susceptible to mumps because their vaccine-based immunity has waned. Booster vaccination programmes for those at high risk of infection during mumps outbreaks - particularly those in congregate living environments - merit priority consideration.

Assessment of mumps virus-specific antibodies by different serological assays: which test correlates best with mumps immunity?

Mumps is one of the vaccine-preventable childhood diseases and it has not yet been eradicated in Germany. This raises the question as to whether the available mumps vaccines are effective enough to prevent mumps and which antibody test system allows the authentic assigning of mumps-specific immunity. In an attempt to answer this question, we analysed 227 sera samples from medical students of the University Hospital Frankfurt/Main, Germany, using different test systems: indirect immune fluorescence, neutralisation assay, routine ELISA and newly developed immunoassays, which contain the mumps nucleoprotein and the wild-type strain Enders ATCC VR106, respectively. Mumps vaccination coverage of the screened collective amounted to 75.1%, which differs notably from the detected mumps-specific seropositivity rates in the literature (range 53.3% to 82.4%). In contrast, a small group of unvaccinated students had much higher seropositivity rates. Of course, assigned vaccination coverage and calculated seropositivity rates are not effective enough to interrupt the transmission of the mumps virus. The often-occurring mumps outbreaks, some in highly vaccinated populations, may not always demonstrate vaccine failure. The investigation of newly developed test systems and the occurrence of different mumps virus genotypes should also be considered.

Mumps outbreaks in four universities in the North West of England: prevention, detection and response

Evidence suggests that primary and secondary vaccine failure have contributed to recent university-based mumps outbreaks. We describe the epidemiology and public health management of two such outbreaks that occurred simultaneously in two areas of the North West of England, affecting four universities, using data from routine surveillance, serology testing, and telephone interviews and electronic questionnaires. Vaccination status was obtained from GP records. Cases were predominantly first year students living in university halls of residence. Public health response involved active surveillance, isolation advice and targeted vaccination clinics. Many students lack natural immunity and mumps vaccination. Factors hindering the public health response include delayed notifications, inability to readily define the 'at risk' population, low vaccine uptake, and lack of an evidence-based, cost effective strategy.

[Mumps transmission control status and inapparent infection rate among middle and high school students during the 2007-2008 mumps outbreak in Daegu]

OBJECTIVES

This study was performed to investigate the mumps transmission control status and inapparent infection rate among middle and high school students in Daegu City during a mumps outbreak.

METHODS

Nine schools (two middle schools and seven high schools), which reported a number of mumps cases between 2007 and 2008 were selected for investigation. During March-May 2008, a standard questionnaire was distributed to gather information about case identification, instructed isolation measure, isolation status of mumps cases and related factors, and outdoor activities of non-isolated mumps case. Inapparent infection rate was estimated by serum mumps IgM and IgG antibodies status and self-reported mumps symptoms in three of the nine schools.

RESULTS

Among 2,560 respondents, more than half of students answered that they did not receive instructions in mumps transmission control measures during the outbreak. Among the 327 mumps cases identified by the questionnaire, 131 cases (40.1%) were considered as isolated and the isolation rates were significantly different among schools, grades, and gender. Of the non-isolated cases, 88.3% continued attending school. Inapparent mumps infection rates were between 56.3% and 70.2%.

CONCLUSIONS

Mumps transmission control was inadequate to control the mumps outbreak. Although high inapparent infection rate would mitigate the transmission control effect of case isolation, this measure is fundamental for infection control. The reasons of this inadequate status need to be explored to develop an effective intervention strategy.

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.

Detection of mumps virus-specific memory B cells by transfer of peripheral blood mononuclear cells into immune-deficient mice

Waning immunity to mumps after one or two doses of the measles, mumps and rubella (MMR) vaccine has been described. Using a human peripheral blood lymphocyte (PBL)-severe combined immunodeficiency (SCID) mouse model, MMR vaccine recipients with undetectable and high antibody titres against mumps were compared for the presence of circulating mumps-specific memory B cells. Peripheral blood mononuclear cells (PBMC) from six donors (three subjects with undetectable and three with high antibody titres against mumps) were injected into the spleens of non-obese diabetic (NOD)-SCID mice (three mice per subject). Mice were pretreated with TMbeta1 and total body irradiation to improve engraftment. In vivo production of human antibodies against mumps was evaluated in mouse plasma on days 7, 10 and 13 with a commercial enzyme-linked immunosorbent assay (ELISA), functional reduction neutralization test. Three donors had mumps antibody titres below the detection limit (titre < 230) and three had high antibody titres (range 5700-7300). None of the mice injected with PBMC from subjects with undetectable antibody titres showed detectable human antibody titres, despite the presence of cell-mediated immunity in two of the three donors. Seven out of nine mice injected with PBMC from subjects with high antibody titres acquired detectable antibody titres for mumps in their plasma. PBMC from vaccinees without detectable serum antibodies against mumps virus were unable to induce secretion of anti-mumps antibodies in the blood of recipient mice, whereas PBMC from vaccinees with high antibody titres were able to do so. This observation suggests that the frequency of mumps-specific memory B cells is very low in vaccinees with undetectable antibody titres. These individuals may therefore be at risk of developing mumps disease upon encounter with wild-type virus.

Detection of Bartonella henselae in domestic cats' saliva

BACKGROUND AND OBJECTIVES

Bartonella species are being recognized as increasingly important bacterial pathogens in veterinary and human medicine. These organisms can be transmitted by an arthropod vector or alternatively by animal scratches or bites. The objectives of this study were to identify contamination of cat's saliva and nail with B. henselae as a causative role to infect human in a sample of the cat population in Iran.

MATERIALS AND METHODS

Blood, saliva and nail samples were collected from 140 domestic cats (stray and pet) from Tehran and Shahrekord and analyzed for the presence of B. henselae with cultural and polymerase chain reaction (PCR) methods and DNA sequencing.

RESULTS

In this study B. henselae was detected in 10.9% of saliva samples (12/110) from pet cats. B. henselae was not detected in nail samples of pet cats (n=110), and in any feral cats' saliva and nail samples (n=30).

CONCLUSION

Our data suggest that pet cats are more likely than stray cats to infect human with B. henselae after a bite and also stray cats can play a role as a reservoir for this bacteria. This is the first report that investigates the presence of B. henselae in cats oral cavity in Iran.

Reemergence of mumps

The mumps virus is a single-stranded, non-segmented, negative-sense RNA virus belonging to the Paramyxoviridae family. Mumps is characterized by bilateral or unilateral swelling of the parotid gland. Aseptic meningitis is a common complication, and orchitis is also common in adolescents and adult men. Diagnosis is based on clinical findings, but because of high vaccination coverage, clinical findings alone are not sufficient for diagnosis, and laboratory confirmation is needed. Mumps is preventable by vaccination, but despite high vaccination coverage, epidemics occur in several countries, including Korea. Many hypotheses are suggested for these phenomena. In this review, we investigate the reason for the epidemics, optimal methods of diagnosis, and surveillance of immunization status for the prevention of future epidemics.

Mumps vaccine effectiveness in highly immunized populations

The aim of the study was to investigate effectiveness of mumps MMR component in communities with high MMR coverage. Outbreak-related cases of mumps born between 1995 and 2005 notified to Navarre and Catalonia public health services during the period 2005-2007 were studied. Vaccine effectiveness (VE) and their 95%CI were calculated using the screening method. Of 47 confirmed, 85.1% immunized with at least one dose (1MMR) and 44.9% with two (2MMR). Estimated VE was 85.4% (95%CI: 67.3-93.4) for 1MMR and 88.5% (95%CI: 78.1-93.9) for 2MMR. High 2MMR coverage, improved confirmation techniques and further VE studies with all confirmed cases are needed to prevent further outbreaks.

Mumps orchitis in the post-vaccine era (1967-2009): a single-center series of 67 patients and review of clinical outcome and trends

Since the introduction of the mumps vaccine, the age of appearance of mumps infection has shifted from children to adolescents and young adults, groups with a higher incidence of disease complications and sequelae. During the years 2000-2001, the Gran Canaria Island was part of an epidemic of mumps. In that period, our institution attended 67 cases of serologically confirmed acute mumps orchitis, the most serious complication of mumps infection in young postpubertal males. We conducted a descriptive and prospective study of this cohort and extensively reviewed the literature from 1967 (the year the first mumps vaccine was introduced) to 2009. Fifty-six patients were admitted because of general impairment and were treated with alpha-interferon. Sixty-six patients presented parotitis previous to orchitis (interval from parotitis to orchitis, 4.9 d). Orchitis was unilateral in 89.5% and bilateral in 10.4% of cases. More than 98% of patients had orchitis-associated fever. Nine patients had clinical and biochemical data showing acute mumps meningitis, and 11 had subclinical pancreatitis. The mean duration of symptoms was 4.6 days (range, 1-9). During the acute phase, more than 41% of the evaluated testes had a volume >25 mL. Acute hormonal disturbances were highly prevalent. These included decreased levels of testosterone and inhibin B with low or normal levels of gonadotropins in 35% of subjects, and, to our knowledge not previously reported, an atypical hormonal pattern consisting of low levels of free testosterone and inhibin B, along with increased measures of luteinizing hormone but low or normal follicle-stimulating hormone levels (11% of cases). During the follow-up period (mean, 331 d) a high incidence of sperm disturbance was found.

The origin and spread of a mumps epidemic: United kingdom, 2003-2006

BACKGROUND

The United Kingdom (UK) underwent a massive epidemic of mumps from 2003 through 2006. The origin and spread was mapped in 350 general practices that used office computers to contribute comprehensive medical information on approximately 3 million patients to the General Practice Research Database (GPRD).

METHODS

The continuous 3-month cumulative incidence of mumps (2003-2006) was estimated by dividing the number of diagnosed cases of mumps each 3 months by the population at risk according to age, region, practice, and calendar time. The effect of the measles, mumps, and rubella (MMR) vaccine was estimated by comparing vaccine exposure of those diagnosed with mumps and those who were not.

RESULTS

There were 5683 cases of mumps recorded in the Database over the 4-year time period. As the Database represents about 5% of the UK population, we estimate that there were more than 100,000 cases of mumps diagnosed in the UK during these 4 years. The epidemic appears to have started in one practice in Wales in the first 6 months of 2003 and then spread slowly north and east, reaching a peak in 2005. Young adults aged 18-24 years were at the highest risk. There were 3 major MMR vaccination campaigns (1988-1989, 1997, and 2004-2005) that by 2006 provided more than 70% protection against mumps in children younger than 18 years of age. Protection was higher in those who had received 2 doses of the vaccine.

CONCLUSION

A comprehensive program of medical information generated by selected general practitioners has provided a sound basis for the real-time recording of the origin, spread, and scope of an infectious disease.

Booster vaccinations: can immunologic memory outpace disease pathogenesis?

Almost all current vaccines work by the induction of antibodies in serum or on the mucosa to block adherence of pathogens to epithelial cells or interfere with microbial invasion of the bloodstream. However, antibody levels usually decline after vaccination to undetectable amounts if further vaccination does not occur. Persistence of vaccine-induced antibodies usually goes well beyond the time when they should have decayed to undetectable levels because of ongoing "natural" boosting or other immunologic mechanisms. The production of memory B and T cells is of clear importance, but the likelihood that a memory response will be fast enough in the absence of a protective circulating antibody level likely depends on the pace of pathogenesis of a specific organism. This concept is discussed with regard to Haemophilus influenzae type b, Streptococcus pneumoniae, and Neisseria meningitidis; hepatitis A and B; diphtheria, tetanus, and pertussis; polio, measles, mumps, rubella, and varicella; rotavirus; and human papilloma virus. With infectious diseases for which the pace of pathogenesis is less rapid, some individuals will contract infection before the memory response is fully activated and implemented. With infectious diseases for which the pace of pathogenesis is slow, immune memory should be sufficient to prevent disease.

Mumps resurgences in the United States: A historical perspective on unexpected elements

In 2006 the United States experienced the largest nationwide mumps epidemic in 20 years, primarily affecting college dormitory residents. Unexpected elements of the outbreak included very abrupt time course (75% of cases occurred within 90 days), geographic focality (85% of cases occurred in eight rural Midwestern states), rapid upward and downward shift in peak age-specific attack rate (5-9-year olds to 18-24-year olds, then back), and two-dose vaccine failure (63% of case-patients had received two doses). To construct a historical context in which to understand the recent outbreak, we reviewed US mumps surveillance data, vaccination coverage estimates, and relevant peer-reviewed literature for the period 1917-2008. Many of the unexpected features of the 2006 mumps outbreak had been reported several times previously in the US, e.g., the 1986-1987 mumps resurgence had extremely abrupt onset, rural geographic focality, and an upward-then-downward age shift. Evidence suggested recurrent mumps outbreak patterns were attributable to accumulation of susceptibles in dispersed situations where the risk of endemic disease exposure was low and were triggered when this susceptible population was brought together in crowded living conditions. The 2006 epidemic followed this pattern, with two unique variations: it was preceded by a period of very high vaccination rates and very low disease incidence and was characterized by two-dose failure rates among adults vaccinated in childhood. Data from the past 80 years suggest that preventing future mumps epidemics will depend on innovative measures to detect and eliminate build-up of susceptibles among highly vaccinated populations.

[Resurgence of mumps in the vaccine era. Factors involved in an outbreak in Navarre, Spain, 2006-2007]

BACKGROUND AND OBJECTIVE

We analysed a mumps outbreak that occurred in Navarre between August 2006 and December 2007, in which vaccinated persons were widely affected.

PATIENTS AND METHODS

Reports of mumps cases were completed by searching primary, emergency and hospital records and laboratory reports. Factors that could affect the occurrence of cases were analysed by birth cohort.

RESULTS

A total of 2866 mumps cases were detected (attack rate 4.7/1000), with 61% of cases in men and a peak incidence at age 19 (inter-quartile range 16-25 years). 14% of cases were confirmed by laboratory: 59 by virus isolation, 14 by PCR and 333 by IgM. The G1 genotype was identified in 7 cases. 21% of cases had been born before 1980 (pre-vaccine cohorts), and 0.2% had not yet reached the vaccination age (15 months). In the cohorts born between 1980 and 2000 (with the opportunity for vaccination), 94.5% of cases had received at least one dose and 88.3%, two doses. 31% of cases occurred in cohorts vaccinated with a first (1995-1997) or second (1986-1988) dose of the Rubini strain. There was also a record of 772 cases who had received two doses of the Jeryl Lynn strain.

CONCLUSIONS

This widespread outbreak is explained by the concurrence of various factors. The current vaccine has substantially reduced the incidence of mumps, but appears unable to totally eliminate virus circulation.

A spatial analysis of the spread of mumps: the importance of college students and their spring-break-associated travel

To characterize the association between county-level risk factors and the incidence of mumps in the 2006 Iowa outbreak, we used generalized linear mixed models with the number of mumps cases per county as the dependent variable. To assess the impact of spring-break travel, we tested for differences in the proportions of mumps cases in three different age groups. In the final multivariable model, the proportion of Iowa's college students per county was positively associated (P<0.0001) with mumps cases, but the number of colleges was negatively associated with cases (P=0.0002). Thus, if the college students in a county were spread among more campuses, this was associated with fewer mumps cases. Finally, we found the proportion of mumps cases in both older and younger persons increased after 1 April (P=0.0029), suggesting that spring-break college travel was associated with the spread of mumps to other age groups.

Effectiveness of Jeryl Lynn-containing vaccine in Spanish children

We evaluated the effectiveness of the Jeryl Lynn strain vaccine in a large outbreak of mumps in Navarre, Spain, 2006-2008. Each of the 241 cases of mumps occurring in children over 15 months of age born between 1998 and 2005 was compared with 5 controls individually matched by sex, birth date, district of residence and paediatrician. Vaccination history was obtained blindly from clinical records. Conditional logistic regression was used to obtain the matched odds ratios (ORs), and effectiveness was calculated as 1-OR. Some 70% of cases had received one dose of measles-mumps-rubella vaccine, and 24% had received two doses. Overall vaccine effectiveness was 72% (95% CI, 39-87%). Two doses were more effective (83%; 54-94%) than a single dose (66%; 25-85%). Among vaccinated children, risk was higher in those who had received the first dose after 36 months of age (OR=3.1; 1.2-8.4) and those who had received the second dose 3 or more years before study enrolment (OR=10.2; 1.5-70.7). Early waning of immunity in children after the second dose may contribute to reduced vaccine effectiveness for mumps prevention.

Relaxation of purifying selection on live attenuated vaccine strains of the family Paramyxoviridae

In wild-type sequences of three paramyxoviruses (measles virus, mumps virus, and Newcastle disease virus), nucleotide diversity at both non-coding sites and at nonsynonymous sites in coding regions was significantly reduced in comparison to that at synonymous sites. Likewise, both the mean and variance of gene diversity at nonsynonymous polymorphic sites were reduced in comparison to non-coding and synonymous sites. Neither of these patterns, which reflect the action of purifying selection against deleterious mutations at nonsynonymous and non-coding sites, were seen in the case of live attenuated vaccine strains, implying that purifying selection has been substantially relaxed on the latter, potentially affecting their biological properties, including antigenicity and vaccine effectiveness. Since the accumulation of mutations increases as a function of the number of generations of replication, these findings highlight the utility of minimizing the number of generations between the original vaccine master seed and the strains used in vaccination, along with periodic monitoring of the extent of sequence evolution.

Rapid response to a case of mumps: implications for preventing transmission at a medical research facility

OBJECTIVE

To prevent transmission among the staff and potentially among the non-human primate (NHP) colony at the U.S. Naval Medical Research Center Detachment in Peru, where an active case of mumps was discovered in a senior laboratory technician in Sep 03, 2007.

MATERIAL AND METHODS

Subjects at the research facility were interviewed and potentially susceptible contacts were tested for mumps IgG.

RESULTS

In total, 81 out of 106 staff members (76%) had close contact with the case. Only 6/81 (7%) had MMR, 33 (41%) reported having had mumps, and 8 of 45 (18%) of the potentially susceptible individuals did not have immunity (IgG > 20.0). All the susceptible, exposed individuals received MMR vaccine. There were no secondary cases and access to the NHP colony was restricted.

DISCUSSION

Immediate and thorough investigation and occupational health response were imperative in preventing secondary cases of mumps among humans and NHP.

Laboratory diagnosis of mumps in a partially immunized population: The Nova Scotia experience

BACKGROUND

In 2007, Atlantic Canada experienced a large outbreak of mumps predominately in university students who had received a single dose of measles, mumps and rubella vaccine. The present study describes the performance characteristics of reverse transcriptase polymerase chain reaction (RT-PCR) on buccal and urine specimens and immunoglobulin M (IgM) serology in this partially immune population.

METHODS

Patients presenting with symptoms suspicious for mumps had a serum, urine and a buccal swab collected for diagnostic testing. Persons were classified as a 'confirmed' case according to the Public Health Agency of Canada's definition. Sera were tested using an enzyme-linked immunoassay. Detection of mumps virus in buccal swabs and urine samples was performed by RT-PCR.

RESULTS

A subset of 155 cases and 376 non-cases that had all three specimens submitted was used for calculating the performance characteristics. The sensitivity of RT-PCR on buccal swabs, urine specimens and IgM serology were 79%, 43% and 25%, respectively. The specificity of RT-PCR on buccal swabs, urine specimens and IgM serology was 99.5%, 100% and 99.7%, respectively. Only 12 of 134 (9%) patients had positive urine specimens in the presence of negative oral swabs.

CONCLUSION

RT-PCR on buccal swabs is the ideal specimen for diagnosis. Testing an additional urine sample in an outbreak setting did not increase the diagnostic yield significantly, but doubled testing volume and cost. In addition, the data suggest that, in this partially immune group, IgM serology has little value in the diagnosis of acute infection.

Recent increases in mumps incidence in Australia: the "forgotten" age group in the 1998 Australian Measles Control Campaign

OBJECTIVES

To describe the epidemiology of mumps and examine potential factors underlying the recent increase in the incidence of mumps in Australia.

DESIGN, SETTING AND PARTICIPANTS

Analytical descriptive study, for all Australian states and territories, of mumps notifications (1994-2007); hospitalisations for mumps (1994-2005); and mumps seroprevalence in a nationally representative sample of 2787 subjects (1997).

MAIN OUTCOME MEASURES

Incidence of notifications and hospitalisations for mumps; seropositivity by birth cohort.

RESULTS

Notified mumps cases increased from 60 in 2002 to 231 in 2005 and 512 in 2007. Between 1994 and 2005, there were 605 hospitalisations for mumps. Mumps seropositivity in all states and territories in 1997 was high (range, 87.1%-94.3%). The predominant age group affected by mumps shifted to adults over time: between 2005 and 2007, 41% of cases occurred among people aged 20-29 years. Cases were concentrated among the birth cohort of 1978 to 1982, who had higher rates of notifications and hospitalisations for mumps and a lower seropositivity rate (92% [95% CI, 89%-94%]) than other birth cohorts.

CONCLUSIONS

The birth cohort of 1978 to 1982 was too old to reliably receive a second dose of measles-mumps-rubella (MMR) vaccine in the 1998 Australian Measles Control Campaign and too young to have had mumps infection. Renewed efforts to maximise two-dose MMR coverage are important for prevention of mumps and measles in young adults.

Mumps: a resurgent disease with protean manifestations

Mumps has re-emerged as an infection in the developed world. Its epidemiology has changed, with the majority of cases now primarily affecting adolescents and adults. While mumps is easily suspected if parotitis is present, parotitis is absent in 10%-30% of symptomatic cases. Mumps is a systemic infection with a variety of extra-parotid complications. In Australia, mumps diagnosis is confirmed by antibody testing and reverse transcriptase-polymerase chain reaction techniques. Suitable specimens for testing are serum, saliva, urine and cerebrospinal fluid. Treatment is generally supportive, although intravenous immunoglobulin therapy may have a future role in mumps management. Interferon alpha-2b treatment may be considered specifically for mumps epididymo-orchitis. Mumps vaccine is included in the measles-mumps-rubella (MMR) vaccine. In Australia, this vaccine is routinely administered at the ages of 1 and 4 years. Serious reactions to the mumps components of the MMR vaccine are rare.

Detection of mumps virus RNA by real-time one-step reverse transcriptase PCR using the LightCycler platform

A real-time reverse transcriptase PCR (RT-PCR) assay that targeted both the mumps virus F gene and human RNase P in clinical samples was adapted for use with the LightCycler platform. LightCycler RT-PCR is as sensitive as conventional nested RT-PCR and significantly less expensive and labor-intensive, making it ideal for mumps diagnosis during outbreaks.

Vaccination coverage and sociodemographic determinants of measles-mumps-rubella vaccination in three different age groups

WHO-Europe's goal is to eliminate measles and rubella by 2010 which will require a coverage rate of 95% for both MMR-vaccine doses. Belgian recommendations include a first MMR vaccine at 12 months and a second at 10-12 years of age. To survey MMR vaccination coverage, EPI two-stage random cluster samples of 1,500 toddlers (18-24 months of age), 900 primary school children (born in 1997), and 1,500 adolescents (born in 1991) living in Flanders (Belgium) were drawn. Documented MMR-vaccination was recorded and a questionnaire on sociodemographic factors was completed at home by trained interviewers in 2005. Missing data were retrieved from well-baby clinics and school health service documents. The overall response rate was 89.5%, leaving 3,490 subjects fit for analysis. MMR coverage (first dose) was 94.0% in the toddler group, 88.0% in the 7-year-olds, and 80.6% in adolescents. The 10- to 12-year dose was documented in 83.6% of the adolescents, but only 74.6% had proof of both MMR vaccines. A lower MMR coverage was noted in single or divorced parents (toddlers, adolescents), families with more than four children (toddlers, adolescents), non-Belgian parental origin (children, adolescents), lower education or unemployment of parents (toddlers, children, adolescents), low family income (children, adolescents), vaccination by the GP (toddlers, children), and education-related factors (children, adolescents). The recommended WHO coverage rate of 95% for MMR is within reach in toddlers. Documentation of vaccination is a major concern in older age groups and may explain lower coverage estimates. Children growing up in a less privileged environment deserve special attention.

Mumps epidemiology and immunity: the anatomy of a modern epidemic

The success of the measles, mumps, and rubella 2-dose vaccination program led public health officials in 1998 to set a goal to eliminate endemic transmission of mumps virus by 2010 in the United States. The large outbreak of mumps in the spring of 2006 has led public health officials to re-evaluate this goal and to recognize that the transmission and epidemiology of mumps in highly vaccinated populations may be different than anticipated. During 2006, a total of 6584 confirmed and probable cases of mumps were reported to the Centers for Disease Control and Prevention and most of these, 5865, occurred between January 1 and July 31. The peak of the outbreak was in April and seemed to be focused on college campuses in 9 midwestern states with Iowa having the highest attack rate. College campuses with mumps outbreaks included ones with 77% to 97% of students having had 2 doses of a mumps vaccine. Diagnosing mumps proved to be problematic in vaccinated persons (ie, laboratory tests seemed to be insensitive and some apparent mumps cases had mild nonclassic illness). The outbreak demonstrated that mumps can sometimes transmit efficiently in highly vaccinated populations and the clinical and laboratory diagnosis of mumps in vaccinated persons is more difficult than in naive persons. The reason for this mumps outbreak is not clear but probably results from multiple factors contributing to an overall increase in susceptibility and/or transmission.

Matched case-control study of effectiveness of live, attenuated S79 mumps virus vaccine against clinical mumps

Mumps virus infection is a potentially serious viral infection of childhood and early adulthood. In China, live, attenuated S(79) mumps virus vaccine has been licensed for pediatric use since 1990. There has been no assessment of its efficacy. Thus, the objective of this study was to determine the effectiveness of live, attenuated S(79) mumps virus vaccine against clinical mumps. Cases were selected from the China Information System for Disease Control and Prevention during September 2004 to March 2005. Each case was matched to a control by gender, age, and area of residency. In all, 469 cases and 469 controls were enrolled in the study. Vaccination information was obtained from the Children's EPI Administrative Computerized System. Vaccine effectiveness (VE) was calculated for one or two doses of S(79) vaccine, with 95% confidence intervals (CI). VE of mumps virus vaccine for one dose versus none was protection of 86.0% (95% CI, 77.2% to 91.5%) of recipients, and VE was much higher in the first 4 years than in the 5 to 12 years after vaccination. The S(79) vaccine can effectively prevent clinical mumps, and a second dose of mumps virus vaccine is necessary for the protection of children in China.

Mumps vaccination coverage and vaccine effectiveness in a large outbreak among college students--Iowa, 2006

Following implementation of a routine childhood two-dose measles-mumps-rubella vaccination strategy, mumps disease levels dropped dramatically in the US and an elimination goal was set for 2010. However, a 2006 epidemic involved >5700 cases nationwide, with many reported among fully vaccinated college students. In an outbreak in two Iowa colleges, we investigated: (1) vaccination coverage using electronic records verified by provider records and (2) vaccine effectiveness assessed by comparison of dose-specific attack rates. Mumps was classified as typical (parotitis/orchitis) or atypical (parotid tenderness or submandibular/sublingual adenitis). Two-dose mumps vaccination coverage was 90% both for the student population (2128/2363) and case-students (97/108). Two-dose vaccine effectiveness was 76-88% with no significant difference for attack rates between one and two doses. Among two-dose vaccine recipients, 74% of the population (1482/2009) and 79% of the case-students (75/95) had received the second dose >10 years before. A large mumps outbreak occurred despite high two-dose vaccination coverage in a population most of whom had received the second dose >10 years before. Two-dose vaccine effectiveness was similar to previous one-dose estimates. Further studies are needed to examine the persistence of two-dose mumps vaccine-induced immunity and to determine whether US mumps elimination can be achieved with the current vaccination strategy.

Molecular identification of two genotypes of mumps virus causing two regional outbreaks in Asturias, Spain

BACKGROUND

In spite of universal vaccination, several sporadic cases of mumps infection, which could produce outbreaks, are detected every year in different countries.

OBJECTIVE

Mumps virus strains causing two regional outbreaks in Asturias (Spain) were phylogenetically characterized.

STUDY DESIGN

Mumps virus strains, which were detected in samples from patients belonging to two regional outbreaks in Asturias, were characterized by sequencing of the SH gene and further alignment to homologous sequences of representative strains of the different mumps genotypes.

RESULTS

Two different strains (Ast/SP02 and Ast/SP07) were isolated. Sequence analysis revealed that while Ast/SP02 belonged to genotype H, Ast/SP07 was phylogenetically close to UK02-19, a reference strain for a new genotype. Both strains belonged to different genotypes from those used in the vaccination (Jeryl-Lynn strain is genotype A).

CONCLUSION

Mumps virus strains different from those used in vaccination program can cause mumps outbreaks even in vaccinated patients.

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.

Real-time reverse transcription-PCR assay for detection of mumps virus RNA in clinical specimens

The mumps virus is a negative-strand RNA virus in the family Paramyxoviridae. Mumps infection results in an acute illness with symptoms including fever, headache, and myalgia, followed by swelling of the salivary glands. Complications of mumps can include meningitis, deafness, pancreatitis, orchitis, and first-trimester abortion. Laboratory confirmation of mumps infection can be made by the detection of immunoglobulin M-specific antibodies to mumps virus in acute-phase serum samples, the isolation of mumps virus in cell culture, or by detection of the RNA of the mumps virus by reverse transcription (RT)-PCR. We developed and validated a multiplex real-time RT-PCR assay for rapid mumps diagnosis in a clinical setting. This assay used oligonucleotide primers and a TaqMan probe targeting the mumps SH gene, as well as primers and a probe that targeted the human RNase P gene to assess the presence of PCR inhibitors and as a measure of specimen quality. The test was specific, since it did not amplify a product from near-neighbor viruses, as well as sensitive and accurate. Real-time RT-PCR results showed 100% correlation with results from viral culture, the gold standard for mumps diagnostic testing. Assay efficiency was over 90% and displayed good precision after performing inter- and intraassay replicates. Thus, we have developed and validated a molecular method for rapidly diagnosing mumps infection that may be used to complement existing techniques.

Mumps outbreaks in Canada and the United States: time for new thinking on mumps vaccines

Mumps epidemics in Canada and the United States prompted us to review evidence for the effectiveness of 5 different vaccine strains. Early trials with the Jeryl Lynn vaccine strain demonstrated an efficacy of approximately 95%, but in epidemic conditions, the effectiveness has been as low as 62%; this is still considerably better than the effectiveness of another safe strain, Rubini (which has an effectiveness of close to 0% in epidemic conditions). The Urabe vaccine strain has an effectiveness of 54%-87% but is prone to cause aseptic meningitis. Little epidemiological information is available for other vaccines. The Leningrad-Zagreb vaccine strain, which is widely used in developing countries and costs a fraction of what vaccines cost in the developed world, seems to have encouraging results; in 1 study, the effectiveness of this vaccine exceeded 95%. Aseptic meningitis has also been reported in association with this vaccine, but the benign nature of the associated meningitis was shown recently in Croatia. Also, the Leningrad-3 strain seems to be effective but causes less-benign meningitis. No mumps vaccine equals the best vaccines in quality, but the virtually complete safety of some strains may not offset their low effectiveness. Epidemiological data are pivotal in mumps, because serological testing is subject to many interpretation problems.