Measles outbreak in Europe: susceptibility of infants too young to be immunized

Seropositivity of measles antibodies in the Israeli population prior to the nationwide 2018 - 2019 outbreak

Measles vaccine is administered in Israel as part of the routine childhood immunization program, at ages 1 and 6 years. In this study, we assessed seropositivity of the Israeli population against measles before the onset and propagation of the 2018-2019 measles outbreak. From the Israel Center for Disease Control National Serum Bank, 3,164 samples collected during 2015 were tested for measles antibodies. All the tests were performed using Enzyme-Linked Immunosorbent Assay (ELISA) commercial kit (Enzygnost, Anti-Measles Virus/IgG: Behring, Marburg, Germany). The overall seropositivity rate for measles was 90.7%. The seropositivity rate at 6 months and younger was 48.9%, and decreased to 3.8% among infants aged 6-11 months. Seropositivity increased to 90.7% in the 1-4-year age group, and reached 96.1% for 5-9 year-old children. Our results suggest high immunity in the Israeli population against measles virus, but not high enough to prevent outbreaks because of pockets of specific population groups with low immunization coverage. Infants between ages 6 and 11 months and children younger than 2 years had the lowest seropositivity rates being the age groups with the highest attack rates of measles during the epidemic of 2018. Efforts should be aimed at avoiding any delay in vaccination once a child reaches the age of 1 year and improving immunity levels in children aged 1-4 years.

Immunogenicity and Safety of an Early Measles Vaccination Schedule at 6 and 12 Months of Age in Human Immunodeficiency Virus (HIV)-Unexposed and HIV-Exposed, Uninfected South African Children

BACKGROUND

Measles morbidity and mortality rates are greatest in children <12 months old, with increased susceptibility in human immunodeficiency virus (HIV)-exposed children. We evaluated the immunogenicity and safety of an early 2-dose measles vaccine regimen administered at 6 and 12 months of age in South Africa.

METHODS

HIV-unexposed (HU) (n = 212) and HIV-exposed, uninfected (HEU) (n = 71) children received measles vaccination (CAM-70) at 6 and 12 months of age. Measles immunoglobulin G titers were measured by means of enzyme-linked immunosorbent assay before and 1 month after each vaccine dose.

RESULTS

The majority of children (88.2% HU and 95.8% HEU; P = .04) were seronegative (<150 mIU/mL) to measles at 4.2 months of age. This was particularly evident among infants of mothers born from 1992 onwards (year of public nationwide measles vaccine availability). One month after the first measles vaccine, 42.3% of HU and 46.4% of HEU children were seropositive (≥330 mIU/mL). After the second dose, the proportion seropositive increased to 99.0% in HU and 95.3% in HEU children. Safety profiles were similar between HU and HEU children.

CONCLUSIONS

Early 2-dose measles vaccination at 6 and 12 months of age was safe and induced antibody responses in HU and HEU children, which could partly offset the early loss of maternally derived antibodies in infants born to predominantly measles-vaccinated mothers.

CLINICAL TRIALS REGISTRATION

NCT03330171.

Effect of age at vaccination on the measles vaccine effectiveness and immunogenicity: systematic review and meta-analysis

Background

The objectives of this review were to evaluate the effect of age at administration of the first dose of a measles-containing vaccine (MCV1) on protection against measles and on antibody response after one- and two-dose measles vaccinations.

Methods

We conducted a systematic review of the PubMed/MEDLINE, Embase, Web of Science and Cochrane databases (1964–2017) to identify observational studies estimating vaccine effectiveness and/or measles attack rates by age at first vaccination as well as experimental studies comparing seroconversion by age at first vaccination. Random effect models were used to pool measles risk ratios (RR), measles odds ratios (OR) and seroconversion RR of MCV1 administered at < 9, 9–11 or ≥ 15 months compared with 12 or 12–14 months of age.

Results

We included 41 and 67 studies in the measles protection and immunogenicity analyses. Older age at MCV1, from 6 to ≥15 months, improved antibody response and measles protection among one-dose recipients. Pooled measles RR ranged from 3.56 (95%CI: 1.28, 9.88) for MCV1 at < 9 months to 0.48 (95%CI: 0.36, 0.63) for MCV1 at ≥15 months, both compared to 12–14 months. Pooled seroconversion RR ranged from 0.93 (95%CI: 0.90, 0.96) for MCV1 at 9–11 months to 1.03 (95%CI: 1.00, 1.06) for MCV1 at ≥15 months, both compared to 12 months. After a second dose, serological studies reported high seropositivity regardless of age at administration of MCV1 while epidemiological data based on few studies suggested lower protection with earlier age at MCV1.

Conclusions

Earlier age at MCV1 decreases measles protection and immunogenicity after one dose and might still have an impact on vaccine failures after two doses of measles vaccine. While two-dose vaccination coverage is most critical to interrupt measles transmission, older age at first vaccination may be necessary to keep the high level of population immunity needed to maintain it.

Early Waning of Maternal Measles Antibodies in Infants in Zhejiang Province, China: A Comparison of Two Cross-Sectional Serosurveys

In China, children aged <8 months, who were expected to be protected by maternal antibodies before receiving the first dose of measles vaccine, were the age group with the greatest risk of infection in recent years. In this study, we evaluated whether infants yet to be age-eligible for measles vaccine had a sufficient seropositive level of maternal measles antibodies in 2009 and 2013. Blood samples were collected from infants aged <8 months through population-based serological surveys conducted in Zhejiang, China. Serum levels of immunoglobulin G measles antibodies were quantified using enzyme-linked immunosorbent assay. In 2013, the mean geometric mean titres (GMTs) of infants aged 4 to 8 months were below the seropositivity threshold (<200 mIU/mL), decreasing from 118.6 mIU/mL (95% confidence interval [CI] 83.0, 169.3 mIU/mL) at 4 months to 28.6 mIU/mL (95% CI 15.6, 52.3 mIU/mL) at 7 months. Antibody levels were significantly lower in 2013 than in 2009 starting from 5 months of age. In conclusion, infants aged 4 to 8 months are susceptible to measles due to low levels of maternal measles antibodies. It is thus suggested to provide infants with a supplementary dose on top of the routine schedule, and/or launch catch-up vaccination campaigns among young women.

Seroepidemiology of measles in Beijing, China: a cross-sectional study

The aim of this study was to assess the seroprevalence of measles and identify the high risk of measles infection in the general population of Beijing. A total of 2144 subjects aged 0-76 years old were selected using a multi-stage stratified sampling method. Socio-demographic characteristics, vaccination history, and disease history of measles were collected by questionnaire. Serum samples were tested for measles-specific IgG by using commercial ELISA kits. The overall seropositivity rate of measles was 79.80% (95% CI 78.1-81.5%) and standardized seropositivity rate was 84.61% (95% CI 84.12-87.10%), with the median concentration of 773.40IU/L. The area of Beijing with the highest seroprevalence was the central area [81.79% (95% CI 80.16-83.42%) and 855.84IU/L]. There were no significant differences in seropositivity rates of different genders (P = 0.074), history of measles infection (P = 0.421) and registered population (P = 0.598). The 1-4 age group had the highest seropositivity rate [94.06%(95% CI 93.06-95.06%)] and children below the age of 1 (0-12 months) had the lowest seropositivity rate [34.42% (95% CI 32.41-36.43%)]. The 30-34 and 35-39 age groups were relatively lower with 72.90% (95% CI 71.02-74.78%) and 74.65% (95% CI 72.81-76.49%) respectively. Seropositivity rates changed along with the incidence rates of measles periodically by years. As shown in the present study, the seroprevalence of measles antibody in Beijing have not yet met the threshold required to achieve measles elimination and therefore the risk of an epidemic of measles will be existing. Appropriate targeted immunization strategies and measures should be considered and carried out.

Measles virus: Background and oncolytic virotherapy

Measles is a highly transmissible disease caused by measles virus and remains a major cause of child mortality in developing countries. Measles virus nucleoprotein (N) encapsidates the RNA genome of the virus for providing protection from host cell endonucleases and for specific recognition of viral RNA as template for transcription and replication. This protein is over-expressed at the time of viral replication. The C-terminal of N protein is intrinsically disordered, which enables this protein to interact with several host cell proteins. It was previously proved in our laboratory that N expressing human cancerous cells undergo programmed cell death because of reactive oxygen species (ROS) generation as well as Caspase 3 activation. The phosphoprotein (P) along with N protein enclosed viral genomic RNA forming a ribonucleoprotein complex (RNP). It also establishes interaction with the large protein (L) i.e. viral RNA dependent RNA polymerase to ensure viral replication within host cells. The host cell receptors of this virus are CD46, SLAM/CD150 and PVRL4. Measles virus is latently oncotropic in nature and possesses oncolytic property by syncytia formation. We try to highlight the application of this property in developing a virotherapeutic vehicle.

Waning of measles maternal antibody in infants in measles elimination settings - A systematic literature review

INTRODUCTION

Most infants are born with immunity to measles through maternal antibodies transferred in pregnancy, which decay over time. However, in measles elimination settings, where measles does not circulate endemically and most immunity is from immunization rather than infection, maternal antibody levels are lower. This results in infant immunity that wanes earlier, and a wider susceptibility gap between maternal antibody decay and infant immunization than in non-eliminated settings. We aimed to systematically quantify the extent and duration of protection from measles in infants in settings that have sustained measles elimination.

METHODS

We conducted a systematic review of studies of measles maternal antibody waning in infants in measles elimination settings. We searched MEDLINE, Embase, CINAHL, Scopus, BIOSIS Previews, and Global Health databases for relevant studies. Studies were included if they were set in countries that had eliminated measles for ≥3 years, and if the study cohort included healthy, full-term, unvaccinated infants ≤12 months, born to healthy mothers, and reported a relevant measure of measles maternal antibody in infants. We assessed study quality using the MetaQAT tool.

RESULTS

We identified 4692 unique citations, eight of which met inclusion criteria. One study reported anti-measles antibody in cord blood, six reported antibody in infant sera, and one reported both. Two studies reported that 80 and 100% of infants were protected from measles at birth. One study reported no protection amongst 3-7 month old infants, and another reported limited protection in infants >4 months. The remaining studies reported the proportion of infants with detected antibody, but not the proportion immune.

CONCLUSION

Although limited, these data suggest that in settings that have sustained measles elimination, some infants are susceptible to measles well before the age of routine measles immunization. Setting-specific seroprevalence and vaccine effectiveness studies are required to evaluate this in different jurisdictions.

Ongoing measles outbreak in Wallonia, Belgium, December 2016 to March 2017: characteristics and challenges

We describe characteristics of an ongoing measles outbreak in Wallonia, Belgium, and difficulties in control measures implementation. As at 12 March 2017, 177 measles cases were notified, of which 50% were 15 years and older, 49% female. Atypical clinical presentation and severe complications, mainly among adults, in combination with late notification, low or unknown vaccination coverage of contacts, infected healthcare workers and increased workload due to contact tracing, are the main concerns for outbreak management.

Attitudes of Swiss Health Care Providers Toward Childhood Immunizations

BACKGROUND

INFOVAC is a network providing information about immunization issues to health professionals. The aim of this study was to assess the attitude of INFOVAC subscribers toward the current Swiss immunization schedule, potential modifications, and current and hypothetical immunization practices regarding their own children.

METHODS

In March 2015, a Web-based survey was sent to 4260 physicians and pharmacists subscribed to INFOVAC. Participation was anonymous and voluntary. The following information was obtained: (1) current immunization status of own children; (2) which immunizations would currently be accepted for a hypothetical own child and (3) attitudes toward potential modifications of the Swiss immunization schedule. Descriptive methods and multivariate models to correct for covariables were used for data analysis.

RESULTS

Nine hundred and fifty-five valid questionnaires were received: 886/3704 (23.9%) from physicians and 69/556 (12.4%) from pharmacists. Current (>95%) and hypothetical (>99%) immunization rates were high for diphtheria, tetanus, pertussis, poliomyelitis and measles-mumps-rubella. Most pediatricians (61%) would support more vaccines for their children than currently recommended by the Swiss immunization advisory committee, whereas about 50% of other physicians and pharmacists would decline at least one of the recommended immunizations, most frequently varicella, pneumococcal or meningococcal C conjugate vaccines. Strong general support was expressed for the expansion of human papillomavirus immunization to males, acceleration of the measles-mumps-rubella schedule and a 2 + 1 instead of 3 + 1 diphtheria-tetanus-pertussis, acellular-inactivated poliomyelitis vaccine (DTPa-IPV)/Haemophilus influenzae type b ± hepatitis B virus (HBV) schedule.

CONCLUSIONS

Survey participants generally demonstrated a positive attitude toward immunization, with pediatricians being the most progressive subgroup with the largest percentage of participants (63.1%) neither declining nor postponing any recommended immunization.

Timeliness and completeness of measles vaccination among children in rural areas of Guangxi, China: A stratified three-stage cluster survey

Background

Large-scale outbreaks of measles occurred in 2013 and 2014 in rural Guangxi, a region in Southwest China with high coverage for measles-containing vaccine (MCV). This study aimed to estimate the timely vaccination coverage, the timely-and-complete vaccination coverage, and the median delay period for MCV among children aged 18–54 months in rural Guangxi.

Methods

Based on quartiles of measles incidence during 2011–2013, a stratified three-stage cluster survey was conducted from June through August 2015. Using weighted estimation and finite population correction, vaccination coverage and 95% confidence intervals (CIs) were calculated. Weighted Kaplan–Meier analyses were used to estimate the median delay periods for the first (MCV1) and second (MCV2) doses of the vaccine.

Results

A total of 1216 children were surveyed. The timely vaccination coverage rate was 58.4% (95% CI, 54.9%–62.0%) for MCV1, and 76.9% (95% CI, 73.6%–80.0%) for MCV2. The timely-and-complete vaccination coverage rate was 47.4% (95% CI, 44.0%–51.0%). The median delay period was 32 (95% CI, 27–38) days for MCV1, and 159 (95% CI, 118–195) days for MCV2.

Conclusions

The timeliness and completeness of measles vaccination was low, and the median delay period was long among children in rural Guangxi. Incorporating the timeliness and completeness into official routine vaccination coverage statistics may help appraise the coverage of vaccination in China.

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The timeliness and completeness of measles vaccination was low.

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The median delay period of measles vaccination was long among Guangxi children.

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Regions with higher measles incidence had higher rates of untimely coverage.

Risk factors for measles infection in 0-7 month old children in China after the 2010 nationwide measles campaign: A multi-site case-control study, 2012-2013

INTRODUCTION

Endemic measles persists in China, despite >95% reported coverage of two measles-containing vaccine doses and nationwide campaign that vaccinated more than 100 million children in 2010. We performed a case-control study in six Chinese provinces during January 2012 through June 2013 to identify risk factors for measles infection among children aged 0-7 months.

METHODS

Children with laboratory-confirmed measles were neighborhood matched with three controls. We interviewed parents of case and control infants on potential risk factors for measles. Adjusted matched odds ratios (mOR) and 95% confidence intervals (CIs) were calculated by multivariable conditional logistic modeling. We calculated attributable fractions for risk factors that could be interpreted as causal.

RESULTS

Eight hundred thirty cases and 2303 controls were enrolled. In multivariable analysis, male sex (mOR 1.6 [1.3, 2.0]), age 5-7 months (mOR 3.9 [3.0, 5.1]), migration between counties (mOR 2.3 [1.6, 3.4]), outpatient hospital visits (mOR 9.4 [6.6, 13.3]) and inpatient hospitalization (mOR 107.1 [48.8, 235.1]) were significant risk factors. The calculated attributable fractions for hospital visits was 43.1% (95% CI: 40.1, 47.5%) adjusted for age, sex and migration.

CONCLUSIONS

Hospital visitation was the largest risk factor for measles infection in infants. Improved hospital infection control practices would accelerate measles elimination in China.

Serological assessment of the establishment of herd immunity against measles in a health district in Malaysia

Background

Malaysia still faces challenges optimizing resources to effectively eliminate measles through high immunization and herd immunity, with sporadic outbreaks of measles as evidence. The objective of this study is to determine the age-specific positive measles antibodies seroprevalence used for assessing the establishment of herd immunity against measles in different age groups. This is useful for identifying vulnerable age groups requiring supplementary immunization.

Methods

A seroprevalence study was conducted among respondents aged 6–9 years, 15–24 years and 45–54 years attending government health clinics in Seremban between September 2014 and January 2015. A total of 1541 measles IgG antibody status were determined using ELISA technique (NovaTec Immundiagnostica GMBH) and assessment of establishment of herd immunity was based on indicators developed by Plans. Data on socio-demographic background as well as medical and medication history were also gathered.

Results

Seropositive rate for all respondents were 87% (95% CI 85–89), while the rest had either indeterminate [6% (95% CI 5–7)] or negative titre [7% (95% CI 6–8)]. None of the factors analyzed except for age were significant predictors of positive measles antibodies. Seropositive rate differed by age with the highest rate seen in adults (94%; CI 92–96), followed by children (90%; 95% CI 87–94) and adolescents, and young adults (74%; 95% CI 70–78). Based on Plans’ indicators, herd immunity was established in adults and children, but not in adolescents and young adults.

Conclusions

To tackle the most susceptible group in the present study, it is advisable to give booster vaccination to secondary school students and freshmen who enter colleges and universities in Malaysia.

What timing of vaccination is potentially dangerous for children younger than 2 years?

Vaccine-preventable diseases still occur although measured coverage rates at 2 y of age are high. The occurrence of these diseases may be explained in part by untimely, that is, late vaccination. Our objective was to identify potentially dangerous vaccination delays for each dose of each vaccine in children younger than 2 y. A 3-round Delphi process was conducted by e-mail. We recruited 37 French experts in vaccines for children: 16 from the Infovac-France group and 21 from the French study group for pediatric infectious diseases. Items were generated by a literature review for the 10 vaccine doses recommended before 2 y of age. Item reduction in round 1 and 2 and any consensus in round 3 used a 70% consensus cutoff. The mean participation rate was 79%. Delays that should not be exceeded were identified for all vaccine doses. The 70% consensus was reached for 6 of the 10 vaccine doses: 15 d after the recommended date for the first 2 doses of the diphtheria-tetanus-acellular pertussis-inactivated polio vaccine/Haemophilus influenzae b vaccine and for the second dose of the pneumococcal conjugate vaccine, 1 month for the meningococcal C vaccine and for the first dose of the measles-mumps-rubella vaccine, and 11 y of age for completion of the hepatitis B vaccination. This Delphi process identified potentially dangerous vaccination delays for children to the age of 2 y. These can be used as new indicators in further studies of vaccine effectiveness and can help to improve the quality of vaccine protection in children.

Hospital preparedness in community measles outbreaks-challenges and recommendations for low-resource settings

We have reviewed various strategies involved in containment of measles in healthcare facilities during community outbreaks. The strategies that are more applicable to resource-poor settings, such as natural ventilation, mechanical ventilation with heating and air-conditioning systems allowing unidirectional air-flow, and protection of un-infected patients and healthcare workers (HCWs), have been examined. Ventilation methods need innovative customization for resource-poor settings followed by validation and post-implementation analysis for impact. Mandatory vaccination of all HCWs with two doses of measles-containing vaccine, appropriate post-exposure prophylaxis of immunocompromised inpatients, and stringent admission criteria for measles cases can contribute toward reduction of nosocomial and secondary transmission within facilities.

Cotreatment of congenital measles with vitamin a and intravenous immunoglobulin

Although the measles vaccine has been part of routine national childhood vaccination programs throughout Europe, measles remains a public health concern. High numbers of cases and outbreaks have occurred throughout the European continent since 2011, and an increasing number of cases have been reported in Turkey since 2012. During a recent measles outbreak in Turkey, 2 pregnant women contracted measles prior to delivering preterm infants at Hacettepe University Hospital. Measles virus genomic RNA and IgM antibodies against measles were detected in the cord blood of infants and mothers in both cases. The infants were treated with intravenous immunoglobulin (IVIG) and vitamin A. Transient thrombocytopenia was present in 1 infant and treated with an additional dose of IVIG and vitamin A. The infants were discharged, without complications, within 10 days of birth. The successful treatment of these cases suggests that infants who have been exposed to, or infected with, measles may benefit from cotreatment of vitamin A and IVIG.

Measles-containing vaccination rates in southern Alberta

Background

Southern Alberta is home to many unique homogeneous communities that typically educate their children in private schools. A number of these communities do not promote immunization as a preventive public health measure, although the reasons behind this vary. People within these communities keep themselves somewhat secluded from other populations and thus do not benefit from overall herd immunity. This has led to frequent outbreaks of vaccine-preventable diseases in private schools affiliated with these homogeneous religious communities.

Objective

To report on low immunization rates of measles, mumps, rubella (MMR) and MMR-varicella in southern Alberta communities and schools and to compare the epidemiology of immunization rates in certain vulnerable communities with those of same-age cohorts in South Zone communities.

Methods

The analysis includes immunization data at the individual level submitted to the provincial immunization repository, Immunization and Adverse Reactions to Immunization, and the Alberta Health Services Meditech module between January 1, 2013, and June 30, 2013.

Results

Heterogeneity of immunization status was found among communities and among schools. The status of two year old children up to date on immunizations ranged from 46.6% in Fort Macleod to 71.9% in Oyen, with a mean of 57.3 children in every 100 up to date. By age seven, the mean percentage of immunized children in southern Alberta was 77.6%, ranging from 57.8% in Picture Butte to 94.6% in Oyen. Immunization status among schools ranged from 17% to 100%, with a mean of 89.3% of children fully immunized and a median of 91% immunized.

Conclusion

There is heterogeneity of immunization uptake for childhood measles-containing vaccine by community and by school in southern Alberta. This study highlights that the location of the school may not align with geographic community as it pertains to immunization rates. Analysis of childhood immunization data at both community and school level is important in understanding the risks of vaccine-preventable illness spread in a given geographic region, such as Alberta South Zone. Data from this study can be used to inform specific interventions required to improve immunization coverage rates in these unique homogeneous cultural communities and their respective schools, and to decrease the risk of measles transmission in Southern Alberta.

Lower transplacental antibody transport for measles, mumps, rubella and varicella zoster in very preterm infants

BACKGROUND

Maternal antibodies, transported over the placenta during pregnancy, contribute to the protection of infants from infectious diseases during the first months of life. In term infants, this protection does not last until the first recommended measles-mumps-rubella vaccination at 14 months in the Netherlands, while these viruses still circulate. The aim of the study was to investigate the antibody concentration against measles, mumps, rubella and varicella (MMRV) in mothers and preterm infants or healthy term infants at birth.

METHODS

Antibody concentrations specific for MMRV were measured in cord blood samples from preterm (gestational age <32 weeks and/or birth weight <1500 g) and term infants, and matched maternal serum samples, using a fluorescent bead-based multiplex immune-assay.

RESULTS

Due to lower placental transfer ratios of antibodies against MMRV in 96 preterm infants (range 0.75-0.87) compared to 42 term infants (range 1.39-1.65), the preterm infants showed 1.7-2.5 times lower geometric mean concentrations at birth compared to term infants. Maternal antibody concentration is the most important determinant of infant antibody concentration against MMRV.

CONCLUSIONS

Preterm infants benefit to a lesser extent from maternal antibodies against measles, mumps, rubella and varicella than term infants, posing them even earlier at risk for infectious diseases caused by these still circulating viruses.

Knowledge and risk perception of measles and factors associated with vaccination decisions in subjects consulting university affiliated public hospitals in Lyon, France, after measles infection

In 2011, a large number of European countries faced measles outbreaks, France accounting for more than half of the reported cases. The Rhône-Alpes region, located in south-east France, was one of the most affected provinces, with an incidence rate of 97.9 cases per 100 000 inhabitants. We conducted a retrospective survey of adults and parents of children consulting university affiliated public hospitals because of measles infections between January 1, 2010 and September 2012 in Lyon, France. Our main objectives were to evaluate (1) the level of study population knowledge of measles, (2) vaccination practices, and (3) changes in opinion with regard to measles vaccination after disease onset. Overall, 73.64% of patients were not vaccinated or partially vaccinated. The main reason for non-vaccination in children was inappropriate age while among non-vaccinated adults, 29.3% could not give any reason. In total, 29.1% of the responding parents and 24.2% of adult cases were opposed to vaccination "in principle." A large number of patients did not recognize measles as a serious illness and were unaware of its complications. Among parents of infected children, knowledge of transmission mode (odds ratio [OR] = 5.9; 95% confidence interval [95% CI]: 1.64-21.26), perceived severity of measles (OR = 1.5; 95% CI: 1.06-2.13), and absence of hepatitis B vaccination (OR = 0.17; 95% CI: 0.04-0.65) were independently associated with a more positive opinion about measles vaccination after disease onset. In adult patients, low education level (OR = 3.39; 95% CI: 1.03-11.11) and lack of knowledge of sequelae (OR = 10.19; 95% CI: 1.14-91.31) were linked with a more positive opinion. Individuals affected by vaccine-preventable diseases are interesting populations to study disease impact on vaccine perception.

Measles epidemic from 1951 to 2012 and vaccine effectiveness in Guangzhou, southern China

BACKGROUND

Since the National Expanded Program on Immunization was implemented in China, considerable progress has been made in reducing the incidence of measles. However, the incidence of measles increased again in 2004. Few post-marketing studies on measles vaccine effectiveness were reported in China. In this study, we aimed to describe the measles epidemic and to evaluate the effectiveness of the measles vaccine in Guangzhou, southern China.

METHODS

Based on the surveillance data for measles, we investigated the epidemiology during different periods between 1951 and 2012. We analyzed the clinical characteristics of laboratory-confirmed cases of measles between 2009 and 2012 and conducted a case-control study using test-negative cases as controls. We determined the protective effect of measles vaccine.

RESULTS

The highest annual incidence in Guangzhou was 2187.15/100,000 in 1964, and the lowest was 0.32/100,000 in 2011. The average incidence of measles from 1951 to 2012 was 306.27/100,000. There was a significant tendency of decline in recent years. From 2009 to 2012, there are 700 laboratory-confirmed cases were reported with an average onset age of 2.5 (median) years. The non-vaccinated target population (age<8 months and ≥ 15 years) accounted for 56.7% of the cases. The transient (non-resident) population accounted for 51.3% of the cases. Fewer cases were observed in the population targeted for measles vaccine (aged 8 months to 14 years). The effectiveness of a single dose of the measles vaccine was 89.1% (95% confidence interval (CI), 44.5-97.9), and the effectiveness of ≥ 2 doses of the measles vaccine was 97.8% (95% CI, 88.3-99.6) in children aged 8 months to 14 years old.

CONCLUSIONS

There is a significant overall decline in the incidence of measles (including clinical and laboratory confirmed cases) in the measles vaccine targeted population in Guangzhou. Two doses of measles vaccine are more effective than one dose in preventing measles in China. In order to accelerate the elimination of measles, vaccination should also be given to the transient and the non-vaccine targeted population.

The effects of weather conditions on measles incidence in Guangzhou, Southern China

BACKGROUND

Few studies were conducted to examine the effects of weather conditions on the incidence of measles.

METHODS

We used a distributed lag nonlinear model (DLNM) to analyze the relationship between meteorological factors and measles incidence in Guangzhou, China.

RESULTS

Nonlinear effects of temperature and relative humidity on measles incidence were observed. The relative risk (RR) for the measles incidence associated with the 75th percentile of mean temperature (27.9 °C) relative to the median of mean temperature (24.7 °C) was 1.00 (0.86,1.16) for lags 0-10 days. The RR for the measles incidence associated with the 25th percentile of relative humidity (64%) relative to the median of relative humidity (73%) was 1.36 (1.01,1.82) for lags 0-30 days. The wet effects and dry effects were larger in females than in males. The wet effects were generally increased with ages. Significantly negative effects of cold spells on measles incidence were observed.

CONCLUSION

Both hot and cold temperatures result in decreases in the incidence of measles, and low relative humidity is a risk factor of measles morbidity. An increased number of measles cases might occur before and after a cold spell. Our findings highlight the need to pay more attention to the weather transformation and improve the immunity of susceptible population for measles elimination. Catch-up vaccination campaigns should be initiated among young adults.

Age-related changes in serological susceptibility patterns to measles: results from a seroepidemiological study in Dongguan, China

The present study was performed to determine the seroprevalence of IgG measles antibodies in Dongguan residents (irrespective of vaccination status), to analyze the changes in age-related serological susceptibility patterns. A total of 1960 residents aged 0-60 years and 315 mother-infant pairs were studied. Serum IgG antibodies against measles virus were measured by ELISA. The overall seroprevalence was 93.4% in the general population in Dongguan, China. In subgroups aged 1-29 years who were likely vaccinated, there was a declining trend of seropositivity with age from 98.6% at 1-4 years to 85.7% at 20-29 years (P<0.0001). Seroprevalence were near or>95% in the older population (30-39 years and ≥ 40 years) who had not been immunized against measles. Age and sex were independent factors associated with seropositivity. Seroprevalence in pregnant women and their newborns was 87.0% and 84.1%, respectively. Our results suggest that the waning vaccine-induced immunity may be the main cause of increased serological susceptibility in young adults and young infants. An additional vaccination strategy that targets young adults is important for elimination of measles.

The epidemiological and clinical characteristics of measles in Wenzhou, China, 2000-2010

This study examined the epidemiological and clinical characteristics of measles in Wenzhou, China. From 2000 to 2010, a total of 13271 measles cases were reported in Wenzhou, with epidemics occurring every 3-4 years. Forty-five per cent of the cases were aged <1 year and 27.2% were aged >14 years. Of 2262 hospitalized measles cases, 66.3% were diagnosed with pneumonia, and three cases died from respiratory failure. The number of measles cases of infants requiring hospitalization increased from birth to age 8 months and declined thereafter. Measurement of serum measles antibody levels in normal infants indicates that over 80% of infants in Wenzhou may be susceptible to measles by age 6 months. The existence of a sufficient pool of unvaccinated children and the decreased level of passively transferred measles antibodies in infants from vaccinated mothers contributed to the sustained transmission observed in Wenzhou.

Large ongoing measles outbreak in a religious community in the Netherlands since May 2013

Despite vaccination coverage over 95%, a measles outbreak started in May 2013 in the Netherlands. As of 28 August, there were 1,226 reported cases, including 82 hospitalisations. It is anticipated that the outbreak will continue. Most cases were orthodox Protestants (n=1,087/1,186; 91.7%) and unvaccinated (n=1,174/1,217; 96.5%). A unique outbreak control intervention was implemented: a personal invitation for measles-mumps-rubella (MMR) vaccination was sent for all children aged 6–14 months living in municipalities with MMR vaccination coverage below 90%.

Obstacles in measles elimination: an in-depth description of a measles outbreak in Ghent, Belgium, spring 2011

Background

From Mid-February to April 2011 one of the largest measles-outbreak in Flanders, since the start of the 2-dose vaccination scheme in 1995, took place in Ghent, Belgium. The outbreak started in a day care center, infecting children too young to be vaccinated, after which it spread to anthroposophic schools with a low measles, mumps and rubella vaccination coverage. This report describes the outbreak and evaluates the control measures and interventions.

Methods

Data collection was done through the system of mandatory notification of the public health authority. Vaccination coverage in the schools was assessed by a questionnaire and the electronic immunization database ‘Vaccinnet’. A case was defined as anyone with laboratory confirmed measles or with clinical symptoms and an epidemiological link to a laboratory confirmed case. Towards the end of the outbreak we only sought laboratory confirmation for persons with an atypical clinical presentation or without an epidemiological link. In search for an index patient we determined the measles IgG level of infants from the day care center.

Results

A total of 65 cases were reported of which 31 were laboratory confirmed. Twenty-five were confirmed by PCR and/or IgM. In 6 infants, too young to be vaccinated, only elevated measles IgG levels were found. Most cases (72%) were young children (0–9 years old). All but two cases were completely unimmunized. In the day care center all the infants who were too young to be vaccinated (N=14) were included as cases. Thirteen of them were laboratory confirmed. Eight of these infants were hospitalized with symptoms suspicious for measles. Vaccination coverage in the affected anthroposophic schools was low, 45-49% of the pupils were unvaccinated. We organized vaccination campaigns in the schools and vaccinated 79 persons (25% of those unvaccinated or incompletely vaccinated).

Conclusions

Clustering of unvaccinated persons, in a day care center and in anthroposophic schools, allows for measles outbreaks and is an important obstacle for the elimination of measles. Isolation measures, a vacation period and an immunization campaign limited the spread of measles within the schools but could not prevent further spread among unvaccinated family members. It was necessary to raise clinicians' awareness of measles since it had become a rare, less known disease and went undiagnosed.

Progress in the elimination of measles and congenital rubella in Central Italy

Despite the launch of a WHO European Region strategic plan 2005-2010 for eliminating measles and rubella and preventing congenital rubella (CR) infection, measles and rubella are still circulating in Europe. Increased transmission and outbreaks of measles in Europe were still observed in 2011. In Italy, the objectives of the National Plan (2003-2007) for measles elimination have not yet been achieved. The goal of measles elimination and incidence reduction of CR cases has been postponed to 2015 by the Italian Ministry of Health through the implementation of the new National Plan 2010-2015 which will require (1) the achievement of more than 95% coverage with 1 dose and two doses of measles containing vaccine (MCV), respectively, within 24 mo and within 12 y of age; (2) supplementary vaccination activities aimed at susceptible populations including adolescents, young adults and those at risk (health care and educational workers, military, groups "hard to reach" like nomads); and in addition, (3) reduction to less than 5% in the proportion of susceptible women of childbearing age (especially immigrant women). Experiences at regional level, like in Tuscany, have shown promising results in order to create an integrated surveillance system between regional and local health authorities, university and laboratory and in the future, to validate elimination. Moreover, the evaluation of all preventive activities performed in Tuscany during the last decade, immunization coverage data, sero-epidemiological population profile and incidence of measles and rubella cases has highlighted critical points which should be improved and good practices already implemented which should be maintained in the future in order to reach the new goals.

A randomized trial to increase acceptance of childhood vaccines by vaccine-hesitant parents: a pilot study

OBJECTIVE

A cluster randomized trial was performed to evaluate an educational intervention to improve parental attitudes and vaccine uptake in vaccine-hesitant parents.

METHODS

Two primary care sites were randomized to provide families with either usual care or an intervention (video and written information) for vaccine-hesitant parents. Eligible parents included those presenting for their child's 2-week well-child visit with performance on the Parent Attitudes about Childhood Vaccines (PACV) survey suggesting vaccine hesitancy (score ≥25). Enrollees completed PACV surveys at the 2-month well-child visit and vaccination status at 12 weeks of age was assessed. The primary outcome was the difference in PACV scores obtained at enrollment and 2 months between the 2 groups. The proportion of on-time vaccination was also compared at 12 weeks.

RESULTS

A total of 454 parents were approached, and 369 (81.3%) participated; 132 had PACV scores of ≥25 and were enrolled, 67 in the control group (mean PACV score 37) and 55 in the intervention group (mean PACV score 40). Two-month PACV surveys were completed by 108 (∼90%) of enrollees. Parents in the intervention group had a significant decrease in PACV score at 2 months compared to control (median difference 6.7, P = .049); this remained significant after adjustment for baseline PACV score, race/ethnicity, and income (P = .044). There was no difference in the on-time receipt of vaccines between groups at 12 weeks.

CONCLUSIONS

A brief educational intervention for vaccine-hesitant parents was associated with a modest but significant increase in measured parental attitudes toward vaccines.