Catch-up Vaccination Campaign Research Articles

Effectiveness of bivalent HPV vaccination against genital HPV DNA-positivity of a catch-up campaign at age 13–16 years compared to routine vaccination at age 12 years: a biennial repeated cross-sectional study

BackgroundThe Netherlands is one of few countries worldwide which has used the bivalent HPV vaccine for girls-only for over a decade. This allows assessment of vaccine effectiveness (VE) against female genital HPV DNA-positivity of this vaccine in an observational post-licencing real-world setting. Additionally, it is unclear whether catch-up vaccination campaigns result in similar VE as routine vaccination. Therefore, type-specific and grouped VE were assessed and compared for women who had been eligible for catch-up vaccination at 13–16 years with those who had been eligible for routine vaccination at 12 years.MethodsPASSYON is a Dutch biennial repeated cross-sectional (2011–2021) study among sexual health clinic clients aged 16–24 years old. Women provided self-collected vaginal samples, questionnaires on demographics and sexual behaviour were administered, and women self-reported HPV vaccination status. Samples were analysed using a PCR-based assay (SPF10-LiPA25). Type-specific and grouped VE estimates, adjusted with propensity score stratification, were assessed against genital positivity for 14 HPV types. VE for targeted and non-targeted genotypes were compared between women who had been eligible for the catch-up and those who had been eligible for routine vaccination.ResultsThe study included 4488 female participants who had been eligible for HPV vaccination and provided genital swabs (1561 eligible for catch-up, 2927 for routine vaccination). Very high VE against genital HPV-16 and HPV-18 was observed (resp. 93.5% and 89.5%) and significant cross-protection against six other genotypes (HPV-31/33/35/45/52/58), varying from 18.0% (HPV-52) to 79.6% (HPV-45). VE estimates were comparable between women who had been eligible for the catch-up campaign and those eligible for routine vaccination: VE HPV-16/HPV-18: 92.2% (95%CI: 87.9–94.9) vs. 91.8% (95%CI: 86.0–95.2).ConclusionsIn real-world settings, the VE of bivalent vaccine is high against targeted genotypes, with cross-protection against 6 other genotypes. Catch-up campaigns up to age 16 years can be as effective as routine vaccination at age 12, although it is recommendable to provide HPV vaccination at an age at which most are likely not sexually active yet. This may inform countries considering catch-up campaigns when introducing or extending the use of HPV vaccination within their national immunisation programmes.

Effect of COVID-19 Pandemic on Routine Immunization at a Tertiary Care Centre

Background The Coronavirus disease 2019 COVID-19 pandemic disrupted healthcare services worldwide impacting routine childhood vaccinations thereby posing the danger of vaccine preventable infections in the near future.Aim This study aimed to assess the occurrence and frequency of delayed vaccinations during the pandemic at a tertiary care center in India. Methods This descriptive record-based study analyzed immunization records of children aged 0-15 years attending the out-patient clinic from March 2019 to August 2021. The study period was divided into pre-COVID lockdown 1 amp 2 and unlock 1 amp 2 phases. Data were analyzed using descriptive statistics and Chi-square tests.Results Vaccination rates significantly decreased during the pandemic compared to the pre-COVID phase particularly during the lockdowns. Maximum reduction was observed with optional vaccines. Unlock phases also showed decreased vaccinations suggesting continued impact of fear and limited accessibility even with easing of restrictions.Conclusion The COVID-19 pandemic significantly disrupted childhood immunizations. Aggressive catch-up vaccination campaigns with effective communication safety precautions and outreach campaigns to the missed communities are necessary to prevent outbreaks of vaccine-preventable diseases.

Evaluation of the effect of reduced-dose pneumococcal conjugate vaccine schedules on vaccine serotype carriage in children and their caretakers in a naïve population in Vietnam: Protocol for a cluster randomized non-inferiority trial.

Introduction: The WHO currently recommends giving pneumococcal conjugate vaccines (PCVs) as three doses - either three doses in infancy with Pentavalent vaccine (3p+0), or two doses in infancy followed by a booster around 12 months (2p+1). However, their high price is a barrier to introduction and sustainability in low and middle-income countries. We hypothesize that a schedule with a single priming and a booster dose (1p+1) may maintain similar levels of protection for the community by sustaining herd immunity, once circulation of vaccine types has been controlled. Methods and analysis: We will conduct a cluster randomized trial with four intervention arms (1p+1, 0p+1, 2p+1, 3p+0) and three unvaccinated clusters in the 27 communes of Nha Trang, central Vietnam. A PCV catch-up vaccination campaign to all children under three years of age will be performed at the start of the trial. The primary endpoint is non-inferiority of the1p+1 schedule if compared to the WHO standard 2p+1 and 3p+0 schedules in reducing vaccine serotype carriage prevalence in infants. We will also explore impact of 0p+1 schedule. A baseline and annual pneumococcal carriage surveys of 6480 participants per survey covering infants, toddlers and their mothers will be conducted. Ethics and dissemination: Ethical approvals were obtained from the ethical review committees of Institute of Tropical Medicine, Nagasaki University (151203149-2) and the Ministry of Health, Vietnam (1915/QD-BYT). The results, interpretation and conclusions will be presented at national and international conferences, and published in peer-reviewed open access journals. Trial registration number: NCT02961231.

An evaluation of the early impact of the COVID-19 pandemic on Zambia's routine immunization program.

Implications of the COVID-19 pandemic for both populations and healthcare systems are vast. In addition to morbidity and mortality from COVID-19, the pandemic also disrupted local health systems, including reductions or delays in routine vaccination services and catch-up vaccination campaigns. These disruptions could lead to outbreaks of other infectious diseases that result in an additional burden of disease and strain on the healthcare system. We evaluated the impact of the COVID-19 pandemic on Zambia's routine childhood immunization program in 2020 using multiple sources of data. We relied on administrative vaccination data and Zambia's 2018 Demographic and Health Survey to project national disruptions to district-specific routine childhood vaccination coverage within the pandemic year 2020. Next, we leveraged a 2016 population-based serological survey to predict age-specific measles seroprevalence and assessed the impact of changes in vaccination coverage on measles outbreak risk in each district. We found minor disruptions to routine administration of measles-rubella and pentavalent vaccines in 2020. This was in part due to Zambia's Child Health Week held in June of 2020 which helped to reach children missed during the first six months of the year. We estimated that the two-month delay in a measles-rubella vaccination campaign, originally planned for September of 2020 but conducted in November of 2020 as a result of the pandemic, had little impact on modeled district-specific measles outbreak risks. This study estimated minimal increases in the number of children missed by vaccination services in Zambia during 2020. However, the ongoing SARS-CoV-2 transmission since our analysis concluded means efforts to maintain routine immunization services and minimize the risk of measles outbreaks will continue to be critical. The methodological framework developed in this analysis relied on routinely collected data to estimate disruptions of the COVID-19 pandemic to national routine vaccination program performance and its impact on children missed at the subnational level can be deployed in other countries or for other vaccines.

Routine child immunizations in India during the COVID-19 pandemic

Disruptions in health service delivery and utilization during the COVID-19 pandemic may have caused many children worldwide to not receive vital preventative health services. We investigate the pandemic’s effects on routine childhood vaccinations in India, which has the world’s largest child immunization program. Using data from the Government of India’s health management information system and interrupted time series analyses, we estimate district-level changes in routine child vaccinations during the pandemic relative to typical monthly vaccinations in the pre-pandemic period. Our results indicate there were significant reductions in child vaccinations during the pandemic, with declines being extremely large in April 2020 when a strict national lockdown was in place. For example, district-level administration of the final required dose in the polio series declined by about 60% in April 2020 relative to the typical monthly vaccination levels observed prior to the pandemic. Vaccinations subsequently increased but largely remained below levels observed before the outbreak of COVID-19. Additional declines in vaccinations occurred in 2021 during the second wave of COVID-19 infections in India. Heterogeneity analyses suggest that vaccinations declined the most in districts with the strictest lockdowns and in districts with low health system capacity at baseline. There is a vital need for corrective actions, such as catch-up vaccination campaigns, to limit the deleterious consequences that will arise for the children who missed routine immunizations during the COVID-19 pandemic.

Modelling the impact of COVID-19 and routine MenACWY vaccination on meningococcal carriage and disease in the UK.

Country-wide social distancing and suspension of non-emergency medical care due to the COVID-19 pandemic will undoubtedly have affected public health in multiple ways. While non-pharmaceutical interventions are expected to reduce the transmission of several infectious diseases, severe disruptions to healthcare systems have hampered diagnosis, treatment, and routine vaccination. We examined the effect of this disruption on meningococcal disease and vaccination in the UK. By adapting an existing mathematical model for meningococcal carriage, we addressed the following questions: What is the predicted impact of the existing MenACWY adolescent vaccination programme? What effect might social distancing and reduced vaccine uptake both have on future epidemiology? Will catch-up vaccination campaigns be necessary? Our model indicated that the MenACWY vaccine programme was generating substantial indirect protection and suppressing transmission by 2020. COVID-19 social distancing is expected to have accelerated this decline, causing significant long-lasting reductions in both carriage prevalence of meningococcal A/C/W/Y strains and incidence of invasive meningococcal disease. In all scenarios modelled, pandemic social mixing effects outweighed potential reductions in vaccine uptake, causing an overall decline in carriage prevalence from 2020 for at least 5years. Model outputs show strong consistency with recently published case data for England.

Dynamic Changes in Hepatitis A Immunity in Regions with Different Vaccination Strategies and Different Vaccination Coverage.

The data on hepatitis A virus (HAV) seroprevalence are critical for the implementation of a universal mass vaccination (UMV) strategy. The latter has not been implemented in Russia; however, regional child vaccination programs have been adopted in some parts of the country. The aim of this study is to assess changes in HAV immunity within the last decade in regions of Russia with different vaccination strategies and different vaccination coverage rates. In regions where UMV has not been implemented and HAV vaccination coverage rates do not exceed the national average, the 50% seroprevalence threshold has shifted in the Moscow region from people aged under 40 years in 2008 to people aged over 59 years in 2020, and from people aged under 30 years to people aged over 40 years in the Khabarovsk region. In two regions (Yakutia and Sverdlovsk), a two-dose-based UMV scheme has been in place since 2011 and 2003, respectively, and in Tuva single-dose child immunization was launched in 2012. These regional programs have resulted in a significant increase in HAV seroprevalence in children and adolescents. In Yakutia, 50% herd immunity had been achieved by 2020 in age groups under 20 years, compared to 20–30% seroprevalence rates in 2008. In the Sverdlovsk region, HAV immunity has increased to >65% over the decade in children aged over 10 years, adolescents and young adults, whereas it declined in older age groups. However, a three-fold drop in HAV immunity has occurred in children under 10 years of age, reflecting a significant decline in vaccination coverage. In Tuva, HAV immunity rates in children under 10 years old increased two-fold to exceed 50% by 2020. These data suggest that UMV should be implemented on a national level. Measures to control vaccination coverage and catch-up vaccination campaigns are recommended in order to maintain the effectiveness of existing HAV vaccination programs.

Catch-up vaccination campaign in children between 6 and 8 years old during COVID-19 pandemic: The experience in a COVID hub in Milan, Italy

BackgroundCOVID-19 has led to disruption in routine immunization programs around the world. Effective strategies need to be developed to address the decline in vaccine coverage to avoid preventable disease outbreaks. Our study reports a 4-days campaign for the catching-up of missed vaccinations in children aged between 6 and 8 years, in Milan, Italy. MethodsThe catch-up vaccination campaign (21st-24th of September 2021) involved children born in 2013, 2014 and 2015. These cohorts, if not already immunized, received the fourth dose of the Diphtheria-Tetanus-acellular Pertussis and Poliomyelitis vaccination (DTaPP4), the second dose of the Measles-Mumps and Rubella vaccination (MMR2) and Chickenpox, according to the Italian vaccine schedule. Results3,943 letters were sent to children with a missing vaccination. 1,315 children, 33% of expected, were vaccinated during the campaign. The 2015 cohort was the one that benefited most from the initiative, 955 children were vaccinated for a total of 1,864 doses administered. This has led to a significant increase of 20.0 percentage points (p.p.) in vaccination coverages for the fourth dose of DTaPP and the second dose of MMR. 214 children for the 2014 cohort and 146 for the 2013 cohort were vaccinated during the following days, these cohorts have been already called previously therefore the participation in the campaign and consequently the increase in vaccination coverages were less substantial. ConclusionsThis experience has demonstrated that a mass vaccination campaign could be a useful tool in catch-up strategies, even during the pandemic. It should be part of a bigger immunization program strategy that also includes efforts to simultaneously strengthen routine immunization services. With the appropriate organizational improvements, this initiative could pave the way for future successful campaigns involving different age groups and vaccinations.

Dynamics in public perceptions and media coverage during an ongoing outbreak of meningococcal W disease in the Netherlands

BackgroundFrom 2015 to 2018, the Netherlands faced an outbreak of invasive meningococcal disease (IMD) caused by serogroup W. To counter the rise in infections, the government introduced a catch-up menACWY vaccination campaign for teenagers in 2018 and 2019. The outbreak situation induced substantial media attention and a run on menACWY vaccines outside the vaccination campaign. This study aimed to gain insights into the dynamics of public perceptions of and responses to the outbreak and the menACWY vaccination, and into the media coverage about the outbreak.MethodsThree repeated surveys (N = 1110) between 2017 and 2019 were sent to parents of teenagers invited for a menACWY catch-up vaccination, other parents, and individuals with no under-age children. These surveys assessed IMD risk perceptions, attitudes towards the menACWY vaccination, trust in involved institutions, and willingness to vaccinate with the menACWY vaccine. Changes in the public perceptions and responses were studied with linear multilevel regression analyses. In addition, 103 national newspaper articles from the period 2017–2019 were thematically coded with themes about IMD and the menACWY vaccination.ResultsThe survey results showed clear increases in perceived IMD severity, positive attitude towards the menACWY vaccination, and willingness to vaccinate over time. Perceived IMD vulnerability remained low across all three waves, and trust in involved institutions increased slightly. Differences between the survey groups were limited. The newspaper articles discussed the rise in infections extensively, the disease symptoms, and the possible fatal outcome of IMD. In addition, while many articles discussed the menACWY vaccine shortage, few discussed the safety or effectiveness of the vaccine.ConclusionThe real-time insights into the interrelated dynamics of public perceptions, responses, and media coverage provide an integrated portrait of the social developments during this outbreak. The focus on IMD severity and the absence of doubt in the public discussion about vaccine safety may have played an important role in the societal response to this outbreak and the recommended vaccine.

Effect of a Nationwide Universal HBV Vaccination Program and Catch-up Vaccination Campaign on HBV Prevalence in Children

Effect of a Nationwide Universal HBV Vaccination Program and Catch-up Vaccination Campaign on HBV Prevalence in Children

Information needs during an emerging outbreak of meningococcal W135 disease in the Netherlands: a study among teenagers, their parents and healthcare professionals

BackgroundTo counter the rise in invasive meningococcal disease (IMD) serogroup W, the Netherlands introduced a menACWY catch-up vaccination campaign for teenagers in 2018 and 2019. Teenagers and parents who have questions or who seek advice from a professional about vaccinations are likely to consult a youth healthcare professional or their general practitioner. This study aimed to appraise the ability of these healthcare professionals to meet the information needs of teenagers and their parents at the start of the vaccination campaign.MethodsWith online surveys, we assessed information needs in teenagers (N = 1603) and parents (N = 1784) concerning IMD and the menACWY vaccination, and in healthcare professionals (N = 520) in their communication with teenagers and parents. We additionally studied healthcare professionals’ expectations of the information needs of teenagers and parents.ResultsWe identified several information needs about IMD and the menACWY vaccination in teenagers, parents and healthcare professionals. Some important commonalities in the information needs in these three groups were found, with regard to the topics IMD prevention, vaccine effectiveness and vaccine protection duration. Healthcare professionals’ expectations of the information needs of teenagers and parents were quite accurate but some important discrepancies were found.ConclusionOur results suggest that healthcare professionals might not have been optimally equipped or prepared for questions from teenagers and their parents at the beginning of the vaccination campaign. We recommend public health institutes to timely assess and meet information needs about new vaccines in healthcare professionals to optimally equip them for consultations.

Protection by vaccination of children against typhoid fever with a Vi-tetanus toxoid conjugate vaccine in urban Bangladesh: a cluster-randomised trial

SummaryBackgroundTyphoid fever remains a major cause of morbidity and mortality in low-income and middle-income countries. Vi-tetanus toxoid conjugate vaccine (Vi-TT) is recommended by WHO for implementation in high-burden countries, but there is little evidence about its ability to protect against clinical typhoid in such settings.MethodsWe did a participant-masked and observer-masked cluster-randomised trial preceded by a safety pilot phase in an urban endemic setting in Dhaka, Bangladesh. 150 clusters, each with approximately 1350 residents, were randomly assigned (1:1) to either Vi-TT or SA 14-14-2 Japanese encephalitis (JE) vaccine. Children aged 9 months to less than 16 years were invited via parent or guardian to receive a single, parenteral dose of vaccine according to their cluster of residence. The study population was followed for an average of 17·1 months. Total and overall protection by Vi-TT against blood culture-confirmed typhoid were the primary endpoints assessed in the intention-to-treat population of vaccinees or all residents in the clusters. A subset of approximately 4800 participants was assessed with active surveillance for adverse events. The trial is registered at www.isrctn.com, ISRCTN11643110.Findings41 344 children were vaccinated in April–May, 2018, with another 20 412 children vaccinated at catch-up vaccination campaigns between September and December, 2018, and April and May, 2019. The incidence of typhoid fever (cases per 100 000 person-years) was 635 in JE vaccinees and 96 in Vi-TT vaccinees (total Vi-TT protection 85%; 97·5% CI 76 to 91, p<0·0001). Total vaccine protection was consistent in different age groups, including children vaccinated at ages under 2 years (81%; 95% CI 39 to 94, p=0·0052). The incidence was 213 among all residents in the JE clusters and 93 in the Vi-TT clusters (overall Vi-TT protection 57%; 97·5% CI 43 to 68, p<0·0001). We did not observe significant indirect vaccine protection by Vi-TT (19%; 95% CI −12 to 41, p=0·20). The vaccines were well tolerated, and no serious adverse events judged to be vaccine-related were observed.InterpretationVi-TT provided protection against typhoid fever to children vaccinated between 9 months and less than 16 years. Longer-term follow-up will be needed to assess the duration of protection and the need for booster doses.FundingThe study was funded by the Bill & Melinda Gates Foundation.

Effectiveness of the SA 14-14-2 Live-Attenuated Japanese Encephalitis Vaccine in Myanmar.

Myanmar is an endemic country for the Japanese encephalitis virus (JEV), and the SA-14-14-2 live-attenuated JEV vaccine was first introduced as a catch-up vaccination campaign in 2017. To determine the effectiveness of vaccination by means of neutralizing antibody titers against JEV, a cross-sectional descriptive study was conducted among five to 15-year-old monastic school children in Mandalay, Myanmar. A total of 198 students who had received vaccines were recruited, and single-time investigation of anti-JEV IgG and neutralizing antibodies against wild-type JEV were determined using anti-JEV IgG ELISA and plaque reduction neutralization tests (PRNT50). All students 100% (198/198) showed positive results on the anti-JEV IgG ELISA, and 87% (172/198) of the students had neutralizing antibodies against JEV six months after immunization. The geometric mean titers of both IgG antibodies and neutralizing antibodies increased with the participants’ age groups, and statistically significant differences in anti-JEV IgG titers were noted across age groups. In this study, we could not investigate the persistence of neutralizing antibodies as only single-time blood collection was done. This study, which is the first report of JEV vaccination among children in Myanmar, showed similar neutralizing antibody production rates among vaccinated individuals as did studies in other countries.

Modelling the Impact of COVID-19 on Meningococcal Carriage and Disease in the UK

Background: Enforced country-wide social distancing and suspension of most non-emergency medical care due to the COVID-19 pandemic will undoubtedly affect public health in multiple ways. While non-pharmaceutical interventions are expected to reduce transmission of several infectious diseases, severe disruptions to healthcare systems have hampered diagnosis, treatment, and routine vaccination. We examine the effect of this disruption on meningococcal disease and vaccination in the UK.Methods: By adapting an existing mathematical model for meningococcal carriage and disease, we address the following questions: a) What is the predicted impact of social distancing on infection rates? b) What effect might reductions in vaccine uptake have on future infection rates? c) Will catch-up vaccination campaigns be necessary for the adolescent MenACWY vaccine?Findings: Model findings indicate that COVID-19 social distancing is expected to have caused significant reductions in the carriage prevalence of meningococcal strains A, C, W, and Y. In all scenarios modelled, pandemic social mixing assumptions outweighed potential falls in vaccine uptake (of 10%, 34%, and 50%). Furthermore, a return to pre-pandemic carriage prevalence is expected to be slow, greater than 20 years.Interpretation: COVID-19 social distancing is expected to have caused significant reductions in the carriage prevalence of meningococcal strains A, C, W, and Y. It seems unlikely that a MenACWY catch-up campaign is necessary due to the persisting low carriage prevalence we predict. Funding Information: Wellcome Trust; NIHR Health Protection Research Unit in Immunisation.Declaration of Interests: Authors have no competing interests to declare.

Using Serology to Anticipate Measles Post-honeymoon Period Outbreaks.

Measles vaccination is a public health ‘best buy’, with the highest cost of illness averted of any vaccine-preventable disease (Ozawa et al., Bull. WHO 2017;95:629). In recent decades, substantial reductions have been made in the number of measles cases, with an estimated 20 million deaths averted from 2000 to 2017 (Dabbagh et al., MMWR 2018;67:1323). Yet, an important feature of epidemic dynamics is that large outbreaks can occur following years of apparently successful control (Mclean et al., Epidemiol. Infect. 1988;100:419–442). Such ‘post-honeymoon period’ outbreaks are a result of the nonlinear dynamics of epidemics (Mclean et al., Epidemiol. Infect. 1988;100:419–442). Anticipating post-honeymoon outbreaks could lead to substantial gains in public health, helping to guide the timing, age-range, and location of catch-up vaccination campaigns (Grais et al., J. Roy. Soc. Interface 2008003B6:67–74). Theoretical conditions for such outbreaks are well understood for measles, yet the information required to make these calculations policy-relevant is largely lacking. We propose that a major extension of serological studies to directly characterize measles susceptibility is a high priority.

The burden of Japanese encephalitis, the catch-up vaccination campaign, and health service providers\u2019 perceptions in Myanmar: 2012\u20132017

BackgroundMyanmar is endemic for Japanese encephalitis (JE) and has experienced several outbreaks in recent years. The vector-borne disease control (VBDC) program has collected hospital-based surveillance data since 1974. There is an urgent need to collate, analyze, and interpret the most recent information. The study aimed to describe (i) hospital-based JE cases and deaths between 2012 and 2017, (ii) a catch-up vaccination campaign in children in 2017, and (iii) health service provider perceptions about JE in one township in 2018.MethodsThis was a cross-sectional study of cases, deaths, and catch-up childhood vaccinations using secondary data from program records and a survey database of health service provider perceptions.ResultsBetween 2012 and 2017, there were 872 JE cases and 79 deaths with a case fatality rate of 91 per 1000; 2016 was the year with most cases and deaths. Most cases (n = 324) and deaths (n = 37) occurred in children aged 5–9 years. Large case numbers were reported in delta and lowland regions (n = 550) and during the wet season (n = 580). The highest case fatality rates were observed in the hills and coastal regions (120 and 112 per 1000, respectively). Nationwide coverage of the catch-up JE vaccination campaign among 13.7 million eligible children was 92%, with coverage lower in the hills and coastal regions (84%) compared with delta and lowland regions and plains (94%). More vaccinations (65%) occurred through school-based campaigns with the remainder (35%) vaccinated through community-based campaigns. Structured interviews in one township showed that service providers (n = 47) had good perceptions about various aspects of JE, although perceived benefits of specific vector control measures were poor: spraying/fumigation (38%), garbage removal (36%), larvicide use (36%), and drainage of standing/stagnant water (32%).ConclusionThe catch-up vaccination campaign was a successful response to high JE case numbers and deaths in children. However, ongoing surveillance for JE needs to continue and be strengthened to ensure comprehensive reporting of all cases, more knowledge is needed on disability in JE survivors, and all attempts must be made to ensure high percentage coverage of vaccination through routine and catch-up campaigns.

High number of hospitalisations and non-classical presentations: lessons learned from a measles outbreak in 2017, Belgium.

We describe and analyse an outbreak of measles that affected Belgium early 2017. In total, 289 cases were reported, mostly (53%) in people 15 years or older. For 133 (46%) vaccination status was unknown and a further 117 (41%) were not vaccinated. According to national guidelines, 83 of the unvaccinated cases (29% of total cases) should have received minimum one dose of vaccine, but did not. One in five cases (21%) did not present with the classical triad of fever, rash and any of coryza, conjunctivitis or cough. Rash was the most sensitive symptom, being absent in only six cases. A large proportion of cases (125/289, 43%) required hospitalisation. In hospitalised patients, the most commonly observed complications were hepatic disorders (present in 58/125 hospitalised patients, 46%). Thirty-six of the cases (12%) were in healthcare workers and nosocomial spread contributed importantly to the outbreak. Older age at presentation, altered clinical presentations and presence of complications like hepatitis can delay the correct diagnosis of measles. Clinicians should maintain a high index of suspicion in any individual presenting with rash. If the elimination target is to be reached, catch-up vaccination campaigns should be intensified and target young adults and health care workers.

Gap in measles vaccination coverage among children aged 9months to 10 years in Ho Chi Minh City, Viet Nam, 2014.

IntroductionWhen Viet Nam launched the Expanded Programme on Immunization in 1981, it covered six vaccines, including measles. Subsequently, Viet Nam experienced a marked reduction in measles infections. A nationwide measles epidemic occurred in April 2014 and an investigation found that 86% of affected children aged 9 months to 10 years were not fully vaccinated; therefore, understanding the reasons for not vaccinating could improve vaccination coverage.MethodWe performed a cross-sectional study to determine vaccination coverage and reasons for non-vaccination among children aged 9 months to 10 years in six districts in Ho Chi Minh City with the highest number of measles cases in 2014. Measles vaccination status of the youngest child in each household was determined and reasons for non-vaccination were investigated. A χ2 test and multiple logistic regression were used to identify independent predictors of full vaccination.ResultsIn total, 207 children were enrolled during the study period in 2014. Full measles vaccination coverage was 55% in these households, and 73% of parents were aware of the importance of measles vaccination to protect their children. We found that the father’s education level (under high school versus high school and above) and the site where the survey was conducted were significantly associated with vaccination status.ConclusionThe vaccination coverage was lower than the coverage reported by district preventive medicine centres of the seven study wards. Lack of the second vaccination was a key obstacle to eliminating the vaccination gap. A catch-up mass vaccination campaign or health promotion of measles vaccination directed towards parents should be considered to improve vaccination coverage.

MenACWY vaccination decisions in the Netherlands: the role of risk perceptions

Abstract Background The Netherlands experiences an unprecedented increase in meningococcal W infections. A national catch-up menACWY vaccination campaign started in October 2018, covering birth cohorts 2001-2005. To understand menACWY vaccination decisions, our study reports on perceptions of risks and their influence on menACWY vaccination intentions during an ongoing outbreak of meningococcal infections. Methods Online surveys were administered in September 2018 among adolescents (AD) targeted for menACWY vaccination (N = 3036) and parents (PA) of these adolescents (N = 3002). Following a mental models approach, survey items addressed knowledge and beliefs of meningococcal disease, the menACWY vaccination and vaccinations in general, and menACWY vaccination intention. Random Forest Analyses were conducted to identify those knowledge and beliefs that strongest predict vaccination intention. Results The response was 52.8% (N = 1603) in AD and 57.1% (N = 1784) in PA. 71% Of AD and 83% of PA indicated a positive vaccination intention. Most respondents perceived meningococcal disease as a severe disease with possible deathly consequences and were aware of transmission routes. Some misbeliefs of vaccines were rather strongly represented, with respectively 35% of AD and 45% of PA thinking that each year a number of children dies due to vaccination side effects. Preliminary results indicate that perceptions of vaccines in general, especially concerning the need for and the effectiveness, were the strongest predictors of vaccination intention in both AD and PA. Conclusions Adolescents and their parents seemed well informed about meningococcal disease, but less about vaccinations. The belief that vaccines are needed and effective in preventing infectious diseases seems to be of more importance in vaccination decisions than other beliefs of disease and vaccination. Future communications need to address the identified misbeliefs and emphasize the need for and effectiveness of vaccines. Key messages MenACWY vaccination intentions are more dependent on beliefs about vaccines in general than on beliefs about meningococcal disease and the menACWY vaccination. The belief that vaccines are needed and effective in preventing infectious diseases is of major importance in menACWY vaccination decisions.

Vaccination status of migrant populations in EU/EEA countries and implications for VPD control

Abstract Background Migrant populations in the EU/EEA are increasingly being associated with outbreaks of vaccine-preventable diseases (VPDs), including the large-scale measles outbreak currently ongoing across Europe; however, it is unclear to what extent migrants represent an under-immunised group in the European context and implications for VPD control. Ensuring high levels of vaccination coverage is a key priority for all countries through the European Vaccine Action Plan, with EU/EEA Member States committed to eliminating measles and rubella, sustaining polio-free status, and controlling hepatitis B infection. We synthesised existing EU/EEA data to assess under-immunisation in migrants (defined as foreign born) residing in EU/EEA countries. Methods We did a systematic review and meta-analysis (PROSPERO CRD42018103666) in accordance with PRISMA guidelines. Inclusion criteria were primary research studies pertaining to vaccination status (measles, mumps, rubella, diphtheria, tetanus, pertussis, polio and Haemophilus influenzae type b [Hib]) in migrants residing in all EU/EEA countries. Pooled prevalence (95% CIs) were calculated for the meta-analysis using a random effects model. Results 56 studies met our criteria (14 EU/EEA countries); 36 studies, which included data from 80,432 migrants, were included in the meta-analysis. Vaccination status of migrants for key VPDs varied substantially, with pooled immunisation coverage well below the herd immunity threshold (HIT) targets for measles 80% (95% CI: 73-87%; HIT 92-95%), mumps 65% (95% CI: 48-82%; HIT 75-86%), and diphtheria 51% (95% CI: 29-73%; HIT 83-86%). Polio type 1 and 2 coverage was high (97% [95% CI: 95-98%]; 95 [95% CI: 92-97%], respectively). Conclusions Migrants represent an under-immunised group in Europe, thus a high priority group for catch-up vaccination. Innovative strategies to engage them in vaccine uptake will be critical if we are to make European targets for the elimination and/or control of key VPDs. Key messages Migrants represent an under-immunised group in Europe and a high priority group for catch-up vaccination campaigns. Innovative strategies to engage them in vaccine uptake will be critical if we are to make European targets for the elimination and control of vaccine-preventable diseases.