Measles vaccination in an increasingly immunized and developed world

Determinants of second-dose measles vaccination dropout in Ethiopia: A community-based matched case-control study

Background

Measles vaccination is the most important public health intervention and a cost-effective strategy to reduce morbidity and mortality in under-five children. Although Ethiopia's government developed a measles elimination strategic plan by 2020, the full coverage of immunization was 43 %. Therefore, this study aimed to identify determinants of second-dose measles vaccination (MCV2) dropout among children aged 24-35 months in East Bale Zone, Ethiopia.

Method

A community-based matched case-control study was conducted among 351 children (117 cases and 234 controls). Children who received the first dose of measles vaccine but did not receive the second dose were cases, and children who received both doses of measles vaccine were control. The matches were based on age and residence. The data were collected using a structured questionnaire, entered into Epi Data 3.1, cleaned, exported, and analyzed using Stata version 16.1. A multivariable conditional logistic regression analysis was performed. Variables with a P value of <0.05 were considered significant determinants of the dependent variable at the 95 % confidence level.

Results

Mothers who were unable to read and write (mAOR: 4.0; 95 % CI: 1.59-10.2), did not receive counseling (mAOR: 3.19; 95 % CI: 1.62-6.27), spent ≥30 min to reach health facilities (mAOR; 2.76, 95 % CI: 1.25-6.1), and did not attend postnatal care (mAOR; 3.46, 95 % CI: 1.58-7.57) were significantly and positively associated with second-dose measles vaccination dropout. In addition, mothers who had poor knowledge of second-dose measles vaccination (mAOR; 3.20, 95 % CI: 1.50-6.70) and waited more than an hour for measles vaccination at health facilities (mAOR; 2.61, 95 % CI: 1.0-6.20) were significantly more likely to experience second-dose measles vaccine dropout.

Conclusions

The key factors associated with second-dose measles vaccination dropout are maternal illiteracy, lack of PNC, inadequate maternal knowledge and poor counseling about MCV2 vaccination, long distances travel to healthcare facilities and extended waiting times at vaccination providing sites. Health extension workers emphasize strengthening home visit programs in catchment households to improve mothers' awareness of measles vaccination.

Pervasive Parental Hesitancy and Resistance towards Measles Rubella Vaccination in Jordan

Measles remains a highly contagious and potentially severe infectious disease, necessitating high vaccine coverage. However, misinformation and measles vaccine hesitancy/resistance have posed significant challenges to achieving this goal. The COVID-19 pandemic further exacerbated these challenges, leading to a measles outbreak in Jordan in 2023. This study aimed to investigate the acceptance of the measles rubella (MR) vaccine among parents in Jordan and to identify its associated determinants. This cross-sectional questionnaire-based study was conducted using a previously Arabic-validated version of the Parental Attitudes towards Childhood Vaccines (PACV) survey instrument. Data collection took place in October 2023, and the final study sample comprised a total of 391 parents, with mothers representing 69.8% of the participants (n = 273). The majority of participating parents expressed either resistance (n = 169, 43.2%) or hesitancy (n = 168, 43.0%) towards MR vaccination, while only 54 participants (13.8%) expressed MR vaccine acceptance. Multivariate analysis revealed that trust in vaccine safety/efficacy, behavior, and having fewer offspring were significantly associated with MR vaccine acceptance. The current study revealed a concerning level of MR vaccine hesitancy/resistance among parents in Jordan, which could signal a public health alarm in the country. Urgent and targeted interventions are strongly recommended to address this issue, including mass campaigns aimed at building trust in the MR vaccine's safety/efficacy. Additionally, there is an urgent need for effective public health initiatives to ensure sufficient measles vaccine coverage to prevent future outbreaks of this serious disease.

Understanding the challenges to COVID-19 vaccines and treatment options, herd immunity and probability of reinfection

Unlike pandemics in the past, the outbreak of coronavirus disease 2019 (COVID-19), which rapidly spread worldwide, was met with a different approach to control and measures implemented across affected countries. The lack of understanding of the fundamental nature of the outbreak continues to make COVID-19 challenging to manage for both healthcare practitioners and the scientific community. Challenges to vaccine development and evaluation, current therapeutic options, convalescent plasma therapy, herd immunity, and the emergence of reinfection and new variants remain the major obstacles to combating COVID-19. This review discusses these challenges in the management of COVID-19 at length and highlights the mechanisms needed to provide better understanding of this pandemic.

Measles Serostatus in Mothers and Their Newborns in Antioquia, Colombia: Implications for Measles Elimination

To describe the serostatus of measles IgG antibodies in pregnant women and newborns, placental transfer, and factors that determine being below the threshold of 150 mIU/mL, a cross-sectional study was conducted. Blood samples of 790 pregnant women at the time of delivery and 734 umbilical cord samples were analyzed from eight hospitals in the Aburrá Valley of Antioquia, Colombia. Measles IgG antibody measurement was performed with ELISA. The proportion of individuals with antibodies < 150 mIU/mL was 13.9% (95% CI: 12.2-15.8) in pregnant women and 11.1% (95% CI: 9.2-13.4) in newborns. The geometric mean of the antibody level of the pregnant women was 552 mIU/mL (95% CI: 504-605) and in the umbilical cord 662 mIU/mL (95% CI: 604-727). A positive correlation between pregnant woman and umbilical cord antibodies was found. The median ratio of measles IgG antibodies in umbilical cord/pregnant woman was 1.22 for all participants. A seroprevalence below the threshold of 150 mIU/mL was found in newborns whose mothers were born between 1983 and 1994, compared with those born before that period, when exposure to the wildtype virus was common (adjusted prevalence ratio: 3.6, 95% CI: 1.3-9.6). These findings suggest that there are gaps in measles immunity among women of childbearing age, before pregnancy. To close this immune gap and support efforts to maintain measles control, serological screening for measles antibodies should be routinely included in reproductive health and antenatal care programs to identify women without immunity who should be vaccinated before pregnancy or after delivery.

Prevalence and management of rubella susceptibility in healthcare workers in Italy: A systematic review and meta-analysis

Introduction

In the pre-vaccination era, all adults acquired immunity status due to natural infections during childhood and adolescence, whereas universal mass vaccination has changed the seroepidemiology of rubella among adults, showing lack of immunity in some subgroups. National and international guidelines recommend evaluating all healthcare workers (HCWs) for their immune status to rubella and possibly vaccinating those who are seronegative. We conducted a systematic review and meta-analysis to estimate the susceptibility rate to rubella among HCWs in Italy and to explore possible options for the management of those found to be susceptible.

Methods

Eight studies were included in the meta-analysis, selected from scientific papers available in the MEDLINE/PubMed and Google Scholar (till page 10) databases between January 1, 2015 and November 30, 2021. The following terms were used for the search strategy: (sero* OR seroprevalence OR prevalence OR susceptibilit* OR immunit* OR immunogenict*) AND (healthcare worker* OR health personnel OR physician* OR nurse OR student*) AND (rubella OR german measles OR TORCH) AND (Italy)

Results

The prevalence of rubella-susceptible HCWs was 9.0 % (95 %CI: 6.4–12.1 %). In a comparison of female vs. male serosusceptible HCWs, the RR was 0.67 (95 %CI = 0.51–0.88). Occupational medicine examinations for rubella screening with possible subsequent vaccination of seronegatives and exclusion of susceptible HCWs from high-risk settings were common management strategies.

Conclusions

HCWs susceptible to rubella are an important epidemiological concern in Italy, and efforts to identify and actively offer the vaccine to this population should be increased.

Measles seroprevalence in persons over one year of age in Chandigarh, India

Measles continues to result in focal outbreaks in India, despite over three decades of universal infant vaccination. The aims of this study were to examine measles immunity in the population of Chandigarh, India, and to compare immunity by vaccination vs. natural infection. In a cross-sectional study of individuals 1-60 years selected from 30 communities within Chandigarh during 2017-2018, measles immunity was assessed using serological surveys. Seropositivity was compared across demographic groups, and by prior history of vaccination and natural history of infection. Among those 1-20 years old, measles seropositivity, and histories of measles vaccination or prior measles diagnosis were separately assessed as outcomes in logistic regression models, with demographic factors as independent variables. Among 1690 participants, 94% were seropositive, and 6% had borderline or negative antibody levels. Of those positive, 30% had prior vaccination, 16% had a history of natural infection, and 54% had an unknown history. Over 50% of individuals among those >20 years old, had unknown history of immunity. In the multivariable regression models, vaccination was more common in younger ages (P < .0001), and in males compared to females (P = .0220), and in those with more education (P < .0001). The majority of the population was seropositive, and seropositivity increased with age. Older age groups were more likely to be protected because of previous natural infection, whereas younger age groups were protected by vaccination. There was inequity in vaccination coverage by gender, and maternal education status.

Seroprevalence of Varicella-Zoster Virus and Measles among Healthcare Workers in a Tertiary Medical Center in Korea

Measles and varicella still occur in the general population despite the widespread vaccination against them, and healthcare workers (HCWs) are still at risk of exposure to these diseases. Here, we evaluated the seroprevalence of measles and varicella-zoster virus (VZV) in HCWs and the trend of seroprevalence according to age, birth year, and occupational group. The serostatuses of measles and VZV of HCWs during new employee medical examinations between October 2015 and October 2021 were included. Thereafter, the trends of seroprevalence according to age, birth year, and occupational groups were evaluated. Overall, 2070 and 1827 HCWs were evaluated for VZV and measles serostatus, respectively. The seroprevalences of VZV and measles were 91% (1884/2070) and 70% (1284/1827), respectively. Younger HCWs had a significantly lower seroprevalence of measles (p = 0.02, age) and VZV (p = 0.003, birth year and p < 0.001, age). The seroprevalence of measles and VZV was significantly higher among doctors and nursing assistants than among nurses and other HCWs (p < 0.001 in both). In conclusion, the seroprevalence of measles and VZV significantly decreased in younger HCWs. Additionally, monitoring the serostatus of measles and VZV and the immunization of susceptible HCWs are required to prepare and control infectious diseases in healthcare facilities.

Hijab or Niqab Interacts with Facemasks Usage at Healthcare Settings in Kabul, Afghanistan: A Multi-Center Observational Study

Purpose: We aimed to understand the extent of facemask usage resulting from the third wave of the COVID-19 pandemic in an Afghan context. In Afghanistan, new COVID-19 variants, low vaccination rates, political turmoil, and poverty interact not only with the third wave of the COVID-19 pandemic but also with facemask usage. Methods: We collected data (n = 1970) by visually observing the usage and type of facemasks used among visitors entering healthcare facilities in Kabul. We conducted an observational study observing the use of facemasks among 1279 men and 691 women. Results: While 71% of all participants adhered to wearing facemasks, 94% of these users wore surgical masks, and 86% wore all types of facemasks correctly. Interestingly, women adhered to wearing facemasks more than men. Specifically, of all the participants who were not wearing masks, 20% were men, and only 8% were women. Even though men were more in number in our study (64.9%), women have a higher adherence rate to wearing facemasks than men. Conclusions: We conclude that gender socialization and expectations of women to wear the niqab or hijab interact with their adherence to wearing facemasks. Additionally, since Afghanistan is one of the poorest countries in the world, which has witnessed a considerable period of political turmoil, we spotlight that our findings are rare in scholarship as they represent a distinct non-Western Islamic society with a low scale of COVID-19 vaccination. Therefore, more research is needed to assess the general population's socioeconomic and geopolitical barriers to facemask use, given that Afghanistan is an underrepresented social context. Our findings are expected to aid health policymakers in developing novel prevention strategies for the country.

Poor Uptake of MMR Vaccine 1-year Post-Measles Outbreak: New York City and Israel

BACKGROUND

In 2018-2019, large outbreaks of measles occurred in Israel and in New York City, driven in part by travel of unimmunized children between the 2 communities.

METHODS

A retrospective chart review was conducted for children tested for measles (March 2018-September 2019) at NYU Langone Health in New York, NY, and in Ramla subdistrict, Israel. Vaccination records were reviewed to determine vaccination status for measles, mumps, and rubella (MMR) at the time of measles testing and 1-year post-testing.

RESULTS

A total of 264 children were tested for measles, and 102 (38.6%) had confirmed measles. Only 20 (19.6%) of measles-positive cases received a full 2-dose course of vitamin A. 82.4% of children with measles were ≥1 year at the time of diagnosis and fully eligible for MMR vaccine. Of the 100 measles-positive cases with available vaccine records, 63 were unvaccinated at testing, and 27 remained unimmunized against MMR 1 year later. At testing, measles-negative children were significantly more likely to have received MMR than measles-positive children (65.4% vs 37%, P < .01). One year later, 70.4% of measles-negative cases and only 57.1% of measles-positive cases had received MMR vaccine (P = .18).

CONCLUSIONS

The majority of measles cases occurred in unimmunized children eligible for vaccination, and >25% of children in both measles-positive and -negative groups remained unimmunized for MMR 1-year post-outbreak. Our results suggest the need for novel, longitudinal vaccination strategies and increased awareness of the role of vitamin A.

Cross-National Comparison of Religion as a Predictor of COVID-19 Vaccination Rates

We examined the effects of religiosity on COVID-19 vaccination rates using a cross-national comparison while controlling for socio-economic factors and culture. Our analysis, conducted on data from 90 countries representing 86% of the world population, showed that Christianity was negatively related to vaccination, while there was no relation with Islam, Buddhism, Hinduism, and nonbelief. The importance of religion, freedom of expression and belief, sex ratio, median age, and almost all cultural factors were not related to vaccination, whereas Human Development Index was. The influence of different religions on vaccination rates has also been described.

Effect of measles prevalence and vaccination coverage on other disease burden: evidence of measles immune amnesia in 46 African countries

BACKGROUND

Measles is highly infectious that leads to a high disease burden among the vulnerable population, especially in developing countries, despite the availability of highly effective measles vaccine. Immune amnesia, the resetting of the immune systems of infected patients, has been observed in developed countries. This paper is the first to use various African countries to evaluate the extent of immune amnesia.

METHODS

We used two panel datasets from 46 African countries between 1990 and 2018 among children, one is the disease prevalence from Global Burden of Disease, and another is on the measles vaccination coverage from WHO/UNICEF Joint Reporting Form. We used panel regression to estimate the effect of measles prevalence or measles vaccination coverage on other disease prevalence (diarrhea, lower respiratory infection, malaria, meningitis, and tuberculosis).

RESULTS

We found the strong evidence that the increase in the measles prevalence led to an increase in other disease prevalence and mortality. We also found that the increase in the measles vaccination coverage decreased the prevalence of and the mortality due to other diseases.

DISCUSSION AND CONCLUSION

Measles vaccination can have a large impact on children's health because not only does it reduce the prevalence of measles cases and deaths but also could it potentially reduce the prevalence of and deaths due to other diseases.

Review of the measles epidemic in children from Central Eastern Europe in the third millennium

Measles is an extremely contagious viral disease. Even though a safe vaccine exists for this disease, it remains one of the leading causes of mortality and morbidity in infants and young children. We aimed to create a retrospective descriptive study in which to analyze the evolution of the measles epidemic at the European level. The documentation was carried out using European Centre for Disease Prevention and Control (ECDC) and World Health Organization (WHO) statistics. At the same time, we present the epidemic's evolution in Romania, using data provided by the Romanian National Institute of Public Health and Ministry of Health. European statistical data indicate a high number of patients diagnosed with measles both among children and adults. All European countries benefit from the measles vaccination in the form of the measles-mumps-rubella (MMR) trivaccine included in their National Vaccination Programme. The vaccination schedule varies from country to country. In the vaccination scheme, most European countries include two doses of the MMR vaccine among the pediatric population. Romania registered a limited number of cases of measles between 1980 and 2015 following the introduction of the measles vaccination in the National Vaccination Programme. Since 2005, the Romanian vaccination schedule includes two doses of MMR trivaccine, administered at 12 months and at 6-7 years. After 2015, as a result of a significant decrease in the number of vaccinated children, Romania is facing a major increase in the cases of measles. Consecutively, a measles epidemic was declared in 2016 and an additional dose of mandatory MMR trivaccine was introduced at the age of 9 months. After 4 years of this schedule of administration, starting with August 2020, the additional dose of MMR administered during infancy has been discontinued. We propose an analysis of the factors that influenced the downward evolution of the measles epidemic in Romania at the beginning of the third millennium. Issues related to the limitation of interpersonal contact in the context of the social distancing imposed by the Sars-CoV-2 virus pandemic are discussed. We consider necessary a detailed documentation of the percentage of new disease cases that will appear in the pediatric population in the near future, in the context of the resumption of daily activity after the reopening of nurseries, kindergartens and schools.

Effect of early measles vaccination on long-term protection: A systematic review

BACKGROUND

In North America, the first dose of a measles-containing vaccine (MCV1) is administered at ≥12 months of age. However, MCV1 may be given to infants <12 months living in highly endemic areas or traveling to these areas. Although an early dose of MCV1 leads to immediate protection, it remains unclear how this impacts long-term immunity.

METHODS

This systematic review and meta-analysis evaluates the impact of MCV1 given at <12 months vs. ≥12 months of age on long-term immunogenicity and vaccine effectiveness, with long-term defined as at least one-year post-vaccination. PubMed, EMBASE, Global Health, Web of Science and Scopus were searched on October 31st, 2019. Studies were included if they included a cohort of infants vaccinated <12 months of age and evaluated long-term immunogenicity, vaccine efficacy, or effectiveness.

RESULTS

A total of 51 texts were identified: 23 reported outcomes related to vaccine effectiveness and 30 to immunogenicity. Infants vaccinated with MCV1 < 12 months of age showed an overall higher risk of measles compared to ≥12 months of age (RR = 3.16, 95% CI: 2.00, 5.01; OR = 2.46, 95% CI: 1.40, 4.32). Risk of measles decreased with increasing age at first vaccination, with those vaccinated with one dose ≥15 months at a lesser risk compared to 12-14 months or <12 months. Measles seroconversion and seropositivity was not affected by age at first vaccination, but antibody levels were significantly lower in the MCV1 < 12-month group (MD = -0.40, 95% CI: -0.71, -0.09).

CONCLUSION

Long-term measles seroconversion and seropositivity did not appear to be affected by age at MCV1, while vaccine effectiveness decreased with younger age. There was not enough evidence to look at the effect of age at MCV1 on immune blunting.

The Changing Global Epidemiology of Measles, 2013-2018

BACKGROUND

Measles incidence and mortality rates have significantly decreased since vaccine introduction. Despite this progress, however, there has been a global resurgence of measles. To understand the current global epidemiology, we analyzed measles surveillance data.

METHODS

We analyzed data on measles cases from 2013-2018 reported to the World Health Organization. Univariate analysis was undertaken based on age, vaccination history, onset year, World Health Organization region, and World Bank income status for the country where the case was reported, and a surrogate indicator of the historical strength of the country's immunization program. Annual incidence and a 2013-2018 mean country incidence per million were calculated.

RESULTS

From 2013 through 2018, there were 899 800 reported measles cases, of which 57% occurred unvaccinated or undervaccinated persons, with an unknown vaccination history in another 30%. Lower-middle-income countries accounted for 66% of cases, 23% occurred in persons ≥15 years of age. In countries with stronger historical vaccination programs and higher country income, case patients had higher median ages.

CONCLUSIONS

Although most measles case patients are <15 years of age, an age shift is seen in countries with a higher income or a stronger historical vaccination program. Countries must strengthen immunization programs to achieve high vaccination coverage; some must undertake strategies to reach persons ≥15 years of age and close immunity gaps.

The relationship between parental source of information and knowledge about measles / measles vaccine and vaccine hesitancy

OBJECTIVES

Based on the hypothesis that sources of information might affect knowledge and vaccine acceptance, our objectives were to study parental characteristics and sources of information regarding measles/measles vaccine, its relationship to correct knowledge and to administration of the measles vaccine.

BACKGROUND

Although measles eradication is potentially achievable, in 2018-2019 a worldwide resurgence of measles and measles-caused deaths occurred. The main driver was incomplete or no vaccination, designated as vaccine hesitancy (VH).

METHODS

A cross-sectional survey of 399 individuals dispersed all over the country was conducted. Research assistants interviewed parents with a 20-question survey which was previously validated. The questionnaire included four sections: demographics, major sources of information on measles/measles vaccine, knowledge about measles/measles vaccine, and status of child's vaccination. Univariate and multivariate analyses explored associations between correct knowledge and VH.

RESULTS

The majority of respondents were between the ages of 25-39 (62%). Of these, 309 (77%) vaccinated their children against measles on time, 32 (8%) vaccinations were incomplete, and 58 (15%) did not vaccinate, for a total VH of 23%. Parents < 30 years-old and those with a single-child vaccinated less frequently (p < 0.001 and p = 0.002, respectively). Internet and social-media were the major source of information for 32% regarding measles/measles vaccine and for 49% regarding the measles outbreak; both sources were negatively associated with correct knowledge (p < 0.001). In the multivariate analysis, knowledge was independently associated with timely vaccine administration (p < 0.001) and internet or social-media as sources with higher VH (OR 2.52, 95%CI 1.18-5.37 and OR 2.44, 95%CI 1.01-5.91, respectively).

CONCLUSIONS

Social-media and internet are a common source of information on measles/measles vaccine (probably on other vaccines as well), and often associated with incorrect knowledge, which relates significantly to VH. Healthcare professionals should be aware of this prevailing behavior and respond accordingly in these platforms, with the aid of experts in social-networking.

Socio-demographic correlates of first dose of measles (MCV1) vaccination coverage in India

Background

Between 2010 and 2018, measles-related mortality had halved in India mainly with effective measles vaccination campaigns and widespread coverage across the states and population subgroups. Despite the commendable vaccination coverage, 2.9 million children in India missed the first dose of measles vaccine (MCV1) in 2017, and many of those vaccinated were not vaccinated at the recommended age (i.e. between 9 and 12 months). This study analyzed pattern and correlates of MCV1 coverage and MCV1 administration at recommended age among children aged 12–23 months in India.

Methods

We used the official data from the recent round of National Family Health Survey (NFHS-4), a nationally representative cross-sectional household survey in India conducted in 2015–16. Descriptive statistics and logistic regression analysis were applied to ascertain the influence of specified socio-demographic variables affecting measles vaccination coverage in India.

Results

The study revealed the distinct variations in coverage of MCV1 between the districts of India. There were also major challenges with age recommended vaccination, with about 15% of eligible children not vaccinated within the recommended age range, attributable to several socio-demographic factors. Significantly, antenatal care utilization of mothers strongly influenced MCV1 coverage and age recommended MCV1 coverage in India. The study also identified that children who missed MCV1 had one or more adverse health risks such as malnutrition, anemia and diarrhea disease.

Conclusions

A socio-economic gradient exists in India’s MCV1 coverage, mediated by antenatal visits, education of mothers, and highlighted socio-demographic factors. Infection with measles was significantly correlated with greater anthropometric deficits among the study cohort, indicating a wider range of benefits from preventing measles infection. Eliminating morbidity and mortality from measles in India is feasible, although it will require efficient expanded program on immunization management, enhanced health literacy among mothers, continuing commitment from central state and district political authorities.

Vaccine hesitancy and the resurgence of vaccine preventable diseases: the way forward for Malaysia, a Southeast Asian country

This study engaged health professionals in in-depth, semi-structured interviews to explore their opinions concerning the issues surrounding vaccine hesitancy in Malaysia and strategies to improve vaccination to stamp the rise of vaccine preventable diseases (VPDs). Opinions on how to address the resurgence of VPDs in the era of increasing vaccine hesitancy were obtained. Eight health professionals, including geriatricians, pediatricians, microbiologists, public health specialists, and family medicine specialists were interviewed. The influence of anti-vaccination propaganda, past-experience of adverse event following immunization (AEFI), perceived religious prohibition, a belief that traditional complementary and alternative medicine (TCAM) use is safer, pseudoscience beliefs, and anti-vaccine conspiracy theories were identified as reasons for refusing to vaccinate. The interplay of social, cultural and religious perspectives in influencing perceived religious prohibition, pseudoscience beliefs, and the use of TCAM contributing to vaccine refusal was found. Five broad themes emerged from the health professionals regarding strategies to address vaccine hesitancy, including establishing an electronic vaccination registry, increasing public awareness initiatives, providing feedback to the public on the findings of AEFI, training of front-line healthcare providers, and banning the dissemination of anti-vaccine information via social media. With regards to identifying strategies to address the resurgence of VPDs, mandatory vaccination received mixed opinions; many viewed supplementary immunization activity and the prevention of travel and migration of unvaccinated individuals as being necessary. In conclusion, the present study identified unique local cultural, traditional and religious beliefs that could contribute to vaccine hesitancy in addition to issues surrounding vaccination refusal similarly faced by other countries around the world. This information are important for the formulation of targeted intervention strategies to stamp vaccine hesitancy in Malaysia which are also a useful guide for other countries especially in the Southeast Asia region facing similar vaccine hesitancy issues.

Measles immunity gaps in an era of high vaccination coverage: A serology study from Taiwan

BACKGROUND

Routine vaccination for children drastically reduces measles cases. Nonetheless, the global resurgence of measles since 2018 highlights the need for evaluating vaccine-induced immunity in an era of high vaccination coverage, especially in international travelers. This study aims to identify high-risk persons via analyzing the impact of age and different vaccination schedules on seroprevalence of measles in a country with high vaccination coverage, attempting to provide suggestions regarding pre-travel measles vaccination in highly immunized countries.

METHOD

We retrospectively collected serological results of measles from Taiwanese travelers during 2008-2017 and middle-aged subjects from community during 2007-2009. Participants were classified by age groups and cohort based on the national immunization program: cohort I (pre-mass vaccination), cohort II (suboptimal measles vaccination), and cohort III (2-dose MMR in childhood). The effects of age group on seropositivity was shown by odds ratio (OR) with 95% confidence interval (CI) in a logistic regression model.

RESULTS

The overall measles seroprevalence was 74.5% (N = 1096, mean age = 31.7 ± 12.3 years), with adolescents having the lowest seropositivity (65.9%) and participants ≥50 years having the highest (89.4%). Seropositivity was significantly higher in cohort I (pre-mass vaccination) compared with the other 2 cohorts (P < 0.0001). The effect of aging on seropositivity was only significant in cohort II (OR = 1.84, 95% CI = 1.13-2.99, P = 0.014 for 30-39 years vs. 20-29 years).

CONCLUSIONS

Waning immunity to measles in adolescents and young adults is a dominant issue in highly vaccinated cohorts. Enhancing pre-travel vaccination against measles can effectively fill the immunity gaps in highly immunized countries.

Evaluating the population measles susceptibility in Tianjin, China

BACKGROUND

Measles is a highly infectious illness requiring herd immunity of 95% to interrupt transmission. China has not reached elimination goals despite high vaccination coverage. We estimated the population susceptibility against measles in Tianjin, China and to tailor awareness raising activities in the measles elimination plan.

METHODS

Age-specific measles seroprevalence was evaluated by Enzyme-Linked Immunosorbent Assay (ELISA) on 12,164 individual aged 0-44 years in 2009-2018. Measles IgG avidity testing was performed to confirm the relationship of the waning immunity after vaccination and secondary vaccination failures (SVF) on 324 confirmed measles cases in 2013-2018.

RESULTS

11,108 samples (91.32%) tested positive for measles IgG, 239 (1.96%) tested as equivocal and 817 (6.72%) were negative. The age distribution of measles cases in Tianjin followed a U-shaped curve and was highest for those at <8 months and again at 20-39 years which correlated closely with the age distribution of measles susceptibility based on measles IgG antibody status (r = 0.72, P < 0.001). The seropositivity rate and antibody geometric mean concentration (GMC) for the 2018 study population were significantly lower (χ² = 7.45, P = 0.006 and t = 12.01, P < 0.001) compared to 2009. The multivariate stepwise logistic regression analysis showed that age and region were the risk factors for both measles seropositivity rate and GMC after vaccination. The proportion of high avidity cases increased with age, being significantly higher in 75.31% of cases in patients aged 30-34 years (χ² = 18.04, P = 0.003).

CONCLUSIONS

High immunization coverage in children alone will not be adequate to realizing sufficient levels of population herd immunity, particularly given that the potential susceptibility window in adult. Implementation of supplemental immunization activity (SIA) targeted to appropriate group aged 30-34 years is recommended.

Reviewing Solutions of Scale for Canine Rabies Elimination in India

Canine rabies elimination can be achieved through mass vaccination of the dog population, as advocated by the WHO, OIE and FAO under the 'United Against Rabies' initiative. Many countries in which canine rabies is endemic are exploring methods to access dogs for vaccination, campaign structures and approaches to resource mobilization. Reviewing aspects that fostered success in rabies elimination campaigns elsewhere, as well as examples of largescale resource mobilization, such as that seen in the global initiative to eliminate poliomyelitis, may help to guide the planning of sustainable, scalable methods for mass dog vaccination. Elimination of rabies from the majority of Latin America took over 30 years, with years of operational trial and error before a particular approach gained the broad support of decision makers, governments and funders to enable widespread implementation. The endeavour to eliminate polio now enters its final stages; however, there are many transferrable lessons to adopt from the past 32 years of global scale-up. Additionally, there is a need to support operational research, which explores the practicalities of mass dog vaccination roll-out and what are likely to be feasible solutions at scale. This article reviews the processes that supported the scale-up of these interventions, discusses pragmatic considerations of campaign duration and work-force size and finally provides an examples hypothetical resource requirements for implementing mass dog vaccination at scale in Indian cities, with a view to supporting the planning of pilot campaigns from which expanded efforts can grow.

Resurgence of measles in the United States: how did we get here?

PURPOSE OF REVIEW

In September 2019, the United States was at risk of losing measles elimination status due to several large-scale outbreaks resulting in more than 1200 confirmed cases across 31 states. This resurgence caps approximately 10 years of increasing incidence, marked by a highly publicized outbreak in 2015 associated with Disneyland when an infected traveler from the Philippines unknowingly spread the virus to susceptible park visitors and the recently ended large outbreak in undervaccinated Orthodox Jewish communities in New York City and Rockland counties. This review highlights current literature elucidating factors associated with current trends in measles epidemiology in the United States, the public health implications of current measles outbreaks and a path forward for addressing challenges contributing to the resurgence of measles in the United States and globally.

RECENT FINDINGS AND SUMMARY

As the most highly transmissible vaccine preventable disease, measles is especially sensitive to changes in herd immunity, the impact of vaccine refusal and globalization. Results highlight the confluence of these factors in current outbreaks, provide tools to predict outbreak risk, demonstrate the growing impact of misinformation and evaluate the impact of policy approaches for outbreak control and prevention.

Vaccine hesitancy and the resurgence of vaccine preventable diseases: the way forward for Malaysia, a Southeast Asian country

This study engaged health professionals in in-depth, semi-structured interviews to explore their opinions concerning the issues surrounding vaccine hesitancy in Malaysia and strategies to improve vaccination to stamp the rise of vaccine preventable diseases (VPDs). Opinions on how to address the resurgence of VPDs in the era of increasing vaccine hesitancy were obtained. Eight health professionals, including geriatricians, pediatricians, microbiologists, public health specialists, and family medicine specialists were interviewed. The influence of anti-vaccination propaganda, past-experience of adverse event following immunization (AEFI), perceived religious prohibition, a belief that traditional complementary and alternative medicine (TCAM) use is safer, pseudoscience beliefs, and anti-vaccine conspiracy theories were identified as reasons for refusing to vaccinate. The interplay of social, cultural and religious perspectives in influencing perceived religious prohibition, pseudoscience beliefs, and the use of TCAM contributing to vaccine refusal was found. Five broad themes emerged from the health professionals regarding strategies to address vaccine hesitancy, including establishing an electronic vaccination registry, increasing public awareness initiatives, providing feedback to the public on the findings of AEFI, training of front-line healthcare providers, and banning the dissemination of anti-vaccine information via social media. With regards to identifying strategies to address the resurgence of VPDs, mandatory vaccination received mixed opinions; many viewed supplementary immunization activity and the prevention of travel and migration of unvaccinated individuals as being necessary. In conclusion, the present study identified unique local cultural, traditional and religious beliefs that could contribute to vaccine hesitancy in addition to issues surrounding vaccination refusal similarly faced by other countries around the world. This information are important for the formulation of targeted intervention strategies to stamp vaccine hesitancy in Malaysia which are also a useful guide for other countries especially in the Southeast Asia region facing similar vaccine hesitancy issues.

Is maternal HIV infection a risk factor for delayed or missed infant measles vaccination in western Kenya?

Measles is a highly infectious virus and one of the leading causes of childhood morbidity and mortality in areas with low immunization rates. Despite the introduction of the measles vaccine preventing about 20 million deaths between 2000 and 2016, there still is a low uptake of the vaccine, especially in low-income countries. Maternal HIV positive status is identified as one of the factors inhibiting the uptake of the measles vaccine in some settings. Using data from a Health and Demographic surveillance system (HDSS), and a Longitudinal Bio-behavioural Survey (LBBS), we assessed the effect of a mother's HIV status on a child's overall uptake of measles vaccine and timeliness in western Kenya. The findings did not show association between a mother's HIV status and a child's receipt of measles vaccine (OR = 0.84, 95% CI: 0.65, 1.08). However, higher socio-economic status (SES) was a positive factor for receipt of timely measles vaccine (OR = 1.34, 95% CI: 1.03, 1.75) for middle, (OR = 1.43, 95% CI: 1.10, 1.86) upper middle, and (OR = 1.51, 95% CI: 1.15, 1.98) higher quintiles as compared to the lower. Consequently, it is imperative to incorporate interventions that target low SES children and those that improve economic status.