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1.
Trends Microbiol ; 2020 Apr 20.
Article in English | MEDLINE | ID: mdl-32359782

ABSTRACT

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.

2.
Pan Afr Med J ; 35(Suppl 1): 2, 2020.
Article in English | MEDLINE | ID: mdl-32373253

ABSTRACT

The recent US measles outbreak is the largest since 1992. It is just a matter of time before measles is introduced into a juvenile custodial setting. Are we prepared? Should we be prepared? This short article addresses steps institutional settings should take to prevent the spread of measles in a contained setting.

3.
Pan Afr Med J ; 35(Suppl 1): 8, 2020.
Article in English | MEDLINE | ID: mdl-32373259

ABSTRACT

Introduction: Guinea, Sierra Leone and Liberia have attained significant reduction in measles incidence between 2004 and 2013. The Ebola outbreak in 2014-2015 in West Africa caused significant disruption of the health service delivery in the three worst affected countries. The magnitude of the impact on the immunization program has not been well documented. Methods: We reviewed national routine immunization administrative coverage data as well as measles surveillance performance and measles epidemiology in the years before, during and after the EVD outbreak in Guinea, Liberia, Sierra Leone. Results: Both Liberia and Guinea experienced a sharp decline of more than 25% in the monthly number of children vaccinated against measles in 2014 and 2015 as compared to the previous years, while there was no reported decline in Sierra Leone. Guinea and Liberia experienced a decline in measles surveillance activity and performance indicators in 2014 and 2015. During this period, there was an increase in measles incidence and a decline in the mean age of measles cases reported in Liberia and Sierra Leone. Guinea started reporting high measles incidence in 2016. All three countries organized measles supplemental immunization activities by June 2015. Liberia achieved 99% administrative coverage, while Guinea and Sierra Leone attained 90.6% and 97.2% coverage respectively. There were no severe adverse events reported during these mass vaccination activities. The disruptive effect of the Ebola outbreak on immunization services was especially evident in Guinea and Liberia. Our review of the reported administrative vaccination coverage at national level does not show significant decline in measles first dose vaccination coverage in Sierra Leone as compared to other reports. This may be due to inaccuracies in coverage monitoring and data quality problems. The increases in measles transmission and incidence in these three countries can be explained by the rapid accumulation of susceptible children. Despite the organization of mass vaccination activities, measles incidence through 2017 has remained higher than the pre-Ebola period in all three countries. Conclusion: The Ebola outbreak in West Africa significantly affected measles vaccination coverage rates in two of the three worst affected countries, and led to persistent gaps in coverage, along with high measles incidence that was documented until two years after the end of the Ebola outbreak. Liberia and Sierra Leone have demonstrated coverage improvements after the end of the Ebola outbreak.

5.
Public Health ; 183: 55-62, 2020 May 17.
Article in English | MEDLINE | ID: mdl-32434087

ABSTRACT

OBJECTIVES: We described the epidemiology and healthcare exposures during a measles outbreak in London and identified factors associated with isolation on arrival to healthcare premises. STUDY DESIGN: We conducted a cohort study including all confirmed measles cases in London residents from February 1, 2016, to June 30, 2016, and semistructured interviews with two infection prevention and control teams (IPCTs). METHODS: We described the outbreak and conducted a multilevel mixed-effects analysis to assess the relationship between sociodemographic and clinical factors and isolation on arrival to healthcare premises. We summarised the interviews. RESULTS: There were 182 cases, mostly aged 17-35 years (46%; 84). Excluding cases younger than one year, 76% (92/120) were unvaccinated, including two healthcare workers. The majority presented with rash (97%; 174), and 42% (70/166) required hospitalisation. Of the recorded cases, 93% of cases (164/178) had visited a healthcare setting during their infectious period (median number of visits = 2). In 33% (59/178) of the visits, the case was isolated on arrival; when not isolated, four healthcare exposures resulted in further transmission. Presenting to the hospital as opposed to a general practitioner (GP) was associated with higher odds of isolation (odds ratio = 2.23, 95% confidence interval = 1.1-4.4) when adjusted for age, gender and presenting with a cough. The IPCT identified measles training using standardised risk assessments by triage nurses in accident and emergency and intelligence regarding measles activity in the community as positive measures to prevent healthcare exposures. CONCLUSIONS: We recommend opportunistic immunisation of unvaccinated young adults by GPs and that occupational health departments ensure their staff are protected against measles. Raising measles awareness in healthcare settings via training or regular sharing of current measles surveillance activity from public health to the IPCT and GP may improve triage and isolation of cases on arrival to healthcare premises.

6.
Epidemiol Serv Saude ; 29(3): e2018208, 2020.
Article in English, Portuguese | MEDLINE | ID: mdl-32428068

ABSTRACT

OBJECTIVE: to report on Family Health Strategy action at a Primary Health Care Unit in addressing the measles epidemic in Fortaleza, CE, Brazil. METHODS: the actions were carried out between September 2013 and December 2015; nineteen suspected measles cases were registered, three of which were confirmed: two children under 1 year old and one 27-year-old man. RESULTS: 16,726 people between 5 and 29 years old were vaccinated, vaccination coverage in the target population was 82.6%; 101% coverage was achieved among children aged 5 to 11 and 76.8% coverage of people aged 12 to 29. CONCLUSION: the strategies used contributed to achieving the vaccination coverage target in the target population, resulting in the population registered in the Health Unit catchment area falling into the category of low risk of measles transmission.

7.
Lancet Infect Dis ; 20(5): 542, 2020 May.
Article in English | MEDLINE | ID: mdl-32243817
8.
BMC Public Health ; 20(1): 381, 2020 Mar 23.
Article in English | MEDLINE | ID: mdl-32293379

ABSTRACT

BACKGROUND: Since 2016, large scale measles outbreaks have heavily affected countries across Europe. In England, laboratory confirmed measles cases increased almost four-fold between 2017 and 2018, from 259 to 966 cases. Several of the 2017-18 measles outbreaks in England particularly affected Romanian and Roma Romanian communities, with the first outbreaks in these communities occurring in Birmingham, Leeds and Liverpool. This study explored factors influencing vaccination behaviours amongst Romanian and Roma Romanian communities in these three cities. METHODS: Across Birmingham, Leeds and Liverpool, we conducted semi-structured interviews with 33 key providers to explore their experience in delivering vaccinations and managing the outbreak response. We also interviewed 9 Romanian women in one of the cities to explore their vaccination attitudes and behaviours. To categorise factors affecting vaccination we applied the 5As Taxonomy for Determinants of Vaccine Uptake (Access, Affordability, Awareness, Acceptance and Activation) during data analysis. RESULTS: Factors related to access and acceptance, such as language and literacy, ease of registering with a general practice, and trust in health services, were reported as the main barriers to vaccination amongst the communities. Concerns around vaccination safety and importance were reported but these appeared to be less dominant contributing factors to vaccination uptake. The active decline of vaccinations amongst interviewed community members was linked to distrust in healthcare services, which were partly rooted in negative experiences of healthcare in Romania and the UK. CONCLUSION: Access and acceptance, dominant barriers to vaccination, can be improved through the building of trust with communities. To establish trust providers must find ways to connect with and develop a greater understanding of the communities they serve. To achieve this, cultural and linguistic barriers need to be addressed. Better provider-service user relationships are crucial to reducing vaccination inequalities and tackling broader disparities in health service access.

10.
Cochrane Database Syst Rev ; 4: CD004407, 2020 04 20.
Article in English | MEDLINE | ID: mdl-32309885

ABSTRACT

BACKGROUND: Measles, mumps, rubella, and varicella (chickenpox) are serious diseases that can lead to serious complications, disability, and death. However, public debate over the safety of the trivalent MMR vaccine and the resultant drop in vaccination coverage in several countries persists, despite its almost universal use and accepted effectiveness. This is an update of a review published in 2005 and updated in 2012. OBJECTIVES: To assess the effectiveness, safety, and long- and short-term adverse effects associated with the trivalent vaccine, containing measles, rubella, mumps strains (MMR), or concurrent administration of MMR vaccine and varicella vaccine (MMR+V), or tetravalent vaccine containing measles, rubella, mumps, and varicella strains (MMRV), given to children aged up to 15 years. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2019, Issue 5), which includes the Cochrane Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to 2 May 2019), Embase (1974 to 2 May 2019), the WHO International Clinical Trials Registry Platform (2 May 2019), and ClinicalTrials.gov (2 May 2019). SELECTION CRITERIA: We included randomised controlled trials (RCTs), controlled clinical trials (CCTs), prospective and retrospective cohort studies (PCS/RCS), case-control studies (CCS), interrupted time-series (ITS) studies, case cross-over (CCO) studies, case-only ecological method (COEM) studies, self-controlled case series (SCCS) studies, person-time cohort (PTC) studies, and case-coverage design/screening methods (CCD/SM) studies, assessing any combined MMR or MMRV / MMR+V vaccine given in any dose, preparation or time schedule compared with no intervention or placebo, on healthy children up to 15 years of age. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data and assessed the methodological quality of the included studies. We grouped studies for quantitative analysis according to study design, vaccine type (MMR, MMRV, MMR+V), virus strain, and study settings. Outcomes of interest were cases of measles, mumps, rubella, and varicella, and harms. Certainty of evidence of was rated using GRADE. MAIN RESULTS: We included 138 studies (23,480,668 participants). Fifty-one studies (10,248,159 children) assessed vaccine effectiveness and 87 studies (13,232,509 children) assessed the association between vaccines and a variety of harms. We included 74 new studies to this 2019 version of the review. Effectiveness Vaccine effectiveness in preventing measles was 95% after one dose (relative risk (RR) 0.05, 95% CI 0.02 to 0.13; 7 cohort studies; 12,039 children; moderate certainty evidence) and 96% after two doses (RR 0.04, 95% CI 0.01 to 0.28; 5 cohort studies; 21,604 children; moderate certainty evidence). The effectiveness in preventing cases among household contacts or preventing transmission to others the children were in contact with after one dose was 81% (RR 0.19, 95% CI 0.04 to 0.89; 3 cohort studies; 151 children; low certainty evidence), after two doses 85% (RR 0.15, 95% CI 0.03 to 0.75; 3 cohort studies; 378 children; low certainty evidence), and after three doses was 96% (RR 0.04, 95% CI 0.01 to 0.23; 2 cohort studies; 151 children; low certainty evidence). The effectiveness (at least one dose) in preventing measles after exposure (post-exposure prophylaxis) was 74% (RR 0.26, 95% CI 0.14 to 0.50; 2 cohort studies; 283 children; low certainty evidence). The effectiveness of Jeryl Lynn containing MMR vaccine in preventing mumps was 72% after one dose (RR 0.24, 95% CI 0.08 to 0.76; 6 cohort studies; 9915 children; moderate certainty evidence), 86% after two doses (RR 0.12, 95% CI 0.04 to 0.35; 5 cohort studies; 7792 children; moderate certainty evidence). Effectiveness in preventing cases among household contacts was 74% (RR 0.26, 95% CI 0.13 to 0.49; 3 cohort studies; 1036 children; moderate certainty evidence). Vaccine effectiveness against rubella is 89% (RR 0.11, 95% CI 0.03 to 0.42; 1 cohort study; 1621 children; moderate certainty evidence). Vaccine effectiveness against varicella (any severity) after two doses in children aged 11 to 22 months is 95% in a 10 years follow-up (rate ratio (rr) 0.05, 95% CI 0.03 to 0.08; 1 RCT; 2279 children; high certainty evidence). Safety There is evidence supporting an association between aseptic meningitis and MMR vaccines containing Urabe and Leningrad-Zagreb mumps strains, but no evidence supporting this association for MMR vaccines containing Jeryl Lynn mumps strains (rr 1.30, 95% CI 0.66 to 2.56; low certainty evidence). The analyses provide evidence supporting an association between MMR/MMR+V/MMRV vaccines (Jeryl Lynn strain) and febrile seizures. Febrile seizures normally occur in 2% to 4% of healthy children at least once before the age of 5. The attributable risk febrile seizures vaccine-induced is estimated to be from 1 per 1700 to 1 per 1150 administered doses. The analyses provide evidence supporting an association between MMR vaccination and idiopathic thrombocytopaenic purpura (ITP). However, the risk of ITP after vaccination is smaller than after natural infection with these viruses. Natural infection of ITP occur in 5 cases per 100,000 (1 case per 20,000) per year. The attributable risk is estimated about 1 case of ITP per 40,000 administered MMR doses. There is no evidence of an association between MMR immunisation and encephalitis or encephalopathy (rate ratio 0.90, 95% CI 0.50 to 1.61; 2 observational studies; 1,071,088 children; low certainty evidence), and autistic spectrum disorders (rate ratio 0.93, 95% CI 0.85 to 1.01; 2 observational studies; 1,194,764 children; moderate certainty). There is insufficient evidence to determine the association between MMR immunisation and inflammatory bowel disease (odds ratio 1.42, 95% CI 0.93 to 2.16; 3 observational studies; 409 cases and 1416 controls; moderate certainty evidence). Additionally, there is no evidence supporting an association between MMR immunisation and cognitive delay, type 1 diabetes, asthma, dermatitis/eczema, hay fever, leukaemia, multiple sclerosis, gait disturbance, and bacterial or viral infections. AUTHORS' CONCLUSIONS: Existing evidence on the safety and effectiveness of MMR/MMRV vaccines support their use for mass immunisation. Campaigns aimed at global eradication should assess epidemiological and socioeconomic situations of the countries as well as the capacity to achieve high vaccination coverage. More evidence is needed to assess whether the protective effect of MMR/MMRV could wane with time since immunisation.

11.
Nat Ecol Evol ; 2020 Apr 27.
Article in English | MEDLINE | ID: mdl-32341514

ABSTRACT

Apart from its global health importance, measles is a paradigm for the low-dimensional mechanistic understanding of local nonlinear population interactions. A central question for spatio-temporal dynamics is the relative roles of hierarchical spread from large cities to small towns and metapopulation transmission among local small population clusters in measles persistence. Quantifying this balance is critical to planning the regional elimination and global eradication of measles. Yet, current gravity models do not allow a formal comparison of hierarchical versus metapopulation spread. We address this gap with a competing-risks framework, capturing the relative importance of competing sources of reintroductions of infection. We apply the method to the uniquely spatio-temporally detailed urban incidence dataset for measles in England and Wales, from 1944 to the infection's vaccine-induced nadir in the 1990s. We find that despite the regional influence of a few large cities (for example, London and Liverpool), metapopulation aggregation in neighbouring towns and cities played an important role in driving national dynamics in the prevaccination era. As vaccination levels increased in the 1970s and 1980s, the signature of spatially predictable spread diminished: increasingly, infection was introduced from unidentifiable random sources possibly outside regional metapopulations. The resulting erratic dynamics highlight the challenges of identifying shifting sources of infection and characterizing patterns of incidence in times of high vaccination coverage. More broadly, the underlying incidence and demographic data, accompanying this paper, will also provide an important resource for exploring nonlinear spatiotemporal population dynamics.

14.
BMC Infect Dis ; 20(1): 251, 2020 Mar 29.
Article in English | MEDLINE | ID: mdl-32223757

ABSTRACT

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.

15.
Lancet Infect Dis ; 20(3): 273-275, 2020 Mar.
Article in English | MEDLINE | ID: mdl-32112752
17.
East Mediterr Health J ; 26(2): 152-160, 2020 Feb 24.
Article in English | MEDLINE | ID: mdl-32141592

ABSTRACT

Background: Despite the wide use of vaccination, measles outbreaks still occur. Aims: This study assessed cases notified during a measles outbreak in northern Sudan in 2011 and the response of the health authorities to contain the outbreak. Methods: The records of all measles cases reported to the River Nile State health ministry in 2011 from the Abu Hamad locality, a gold-mining area, were reviewed together with the actions of the health authorities at the time of the outbreak. Seventeen gold-mining clusters were included. Data on demographic, clinical, geographic and chronological characteristics of the cases were extracted. Results: The outbreak occurred from 27 January to 3 May 2011 with the peak in epidemiological week 9. A total of 445 measles cases were recorded, giving an incidence of 27.1 per 10 000 of the mining and resident population. Most cases (87.4%) were aged between 15 and 34 years. High fever was the most common symptom (99.3% of the cases), followed by conjunctivitis (80.4%); haemorrhage was recorded in 29.4%. Most cases (84.9%) were unvaccinated. Six deaths occurred (case fatality: 1.3%); two from cerebral coma and four from haemorrhagic shock. Severity of disease was significantly associated with place of origin of the cases (P = 0.003). Conclusion: The measles outbreak in the gold-mining areas in Abu Hamad had serious consequences attributed to poor environmental conditions, overcrowding, poor nutrition and lack of vaccination. The health authority response helped end the outbreak. The local health authority should consider the gold-mining areas as a potential risk to public health in their future plans.


Subject(s)
Measles Vaccine/administration & dosage , Measles/epidemiology , Public Health , Adolescent , Adult , Child , Child, Preschool , Demography , Disease Outbreaks , Female , Humans , Immunization Programs , Male , Measles/prevention & control , Sudan/epidemiology , Vaccination Coverage , Young Adult
18.
J Epidemiol Glob Health ; 10(1): 46-58, 2020 Mar.
Article in English | MEDLINE | ID: mdl-32175710

ABSTRACT

BACKGROUND AND OBJECTIVES: Europe has experienced a major resurgence of measles in recent years, despite the availability and free access to a safe, effective, and affordable vaccination measles, mumps and rubella vaccine (MMR). The main driver for this is suboptimal vaccine coverage. The three objectives of this study are to synthesize and critically assess parental attitudes and beliefs toward MMR uptake, to develop strategies and policy recommendations to effectively improve MMR vaccine uptake accordingly, and ultimately to identify areas for further research. METHODS: A systematic review was conducted using primary studies from PubMed, Medline, Embase, and Scopus published between 2011 and April 2019. Inclusion criteria comprised primary studies in English conducted in Europe and studying parental attitudes and behavior regarding MMR uptake. Data were extracted using an inductive grounded theory approach. RESULTS: In all, 20 high-quality studies were identified. Vaccine hesitancy or refusal were mainly due to concerns about vaccine safety, effectiveness, perception of measles risk and burden, mistrust in experts, and accessibility. Factors for MMR uptake included a sense of responsibility toward child and community health, peer judgement, trust in experts and vaccine, and measles severity. Anthroposophical and Gypsy, Roma, and Traveler populations presented unique barriers such as accessibility. CONCLUSION: A multi-interventional, evidence-based approach is vital to improve confidence, competence, and convenience of measles vaccination uptake. Healthcare professionals need an understanding of individual contextual attitudes and barriers to MMR uptake to tailor effective communication. Effective surveillance is needed to identify under-vaccinated populations for vaccination outreach programs to improve accessibility and uptake.

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