Second Dose Of Measles Vaccine Research Articles

Ongoing Measles in the Developed and Developing World.

Measles is a vaccine-preventable illness. Nevertheless, in recent years, measles is still endemic and epidemic in both the developed world and the developing world. The public perception of measles in the past was that it was not a big deal. However, measles is associated with a number of complications which can be places in three categories which are: acute(diarrhea, otitis media, pneumonia, encephalitis, seizures, and death) and delayed-subacute sclerosing panencephalitis (SSPE) and post-measles immune amnesia. Contrary to the beliefs of the anti-vaccine lobby, measles is bad. In acute measles, the death rate is 1-3 per 1000 and the risk of encephalitis is 1 per 1000. Relatively recent investigations indicate that SSPE is considerably more common than previously believed. The worldwide contribution of post-measles immune amnesia to morbidity and mortality is likely to be huge. In exposure situations, two doses of measles vaccine will prevent 99% of cases. Presently in the United States, the first dose is given at 12 through 15 months of age. The second dose is most often administered at 4 through 6 years of age. In my opinion, the second dose of measles vaccine should be given 4-6 weeks after the first dose rather than at 4-6 years of age. Children who don't have antibody to measles should not travel to risk areas.

Predictors for low coverage of uptake of second dose of measles vaccine among children in sub-Saharan Africa, 2023: a systematic review and meta-analysis.

Measles became a public health important disease in sub-Saharan Africa. World Health Organization recommended measles-containing vaccine dose 2 (MCV2) through routine service delivery. This study aims to determine coverage of second-dose measles vaccination uptake and its predictors among children aged 24-35 months in sub-Saharan Africa. We conducted an extensive search of literature as indicated in the guideline of reporting systematic review and meta-analysis (PRISMA). The databases used were PubMed, Google Scholar, and HINARI literature. The overall uptake of the second dose of measles vaccine uptake was 41% (95% CI: 28.90-53.47). Caregiver's awareness of the importance of the second dose of measles (2.51, 95% CI 1.77, 3.25), educational status of mothers (1.30, 95% CI 1.16, 1.45), distance from vaccination site (1.22, 95% CI 1.12, 1.32), and attending four and above ANC visit (2.72, 95% CI 2.29, 3.15) were determinants for second dose measles vaccine uptake. Coverage of the second dose of measles uptake in Sub-Saharan Africa was low (41%) which is lower than the recommendation from WHO. Therefore policymakers and stakeholders should increase mother's awareness. Also, special strategies should be developed for those who are far from the vaccination site. ANC: Ante Natal Care; JBI: Joanna Briggs Institute; MCV1: Measles containing vaccine dose 1; MCV2: Measles containing vaccine dose 2; WHO: World Health Organization.

Determinants of Measles Vaccine Uptake among Mothers of Children between 9 and 24 Months in Narok North Subcounty

The low uptake of measles vaccines in Kenya is a noticeable public health problem. Therefore, the study assessed the determinants of low uptake and hesitancy of measles vaccination among mothers of children aged 9 – 24 months in Narok North Sub-County, Narok. Cross-sectional quantitative study was done. The study was conducted in four purposively selected health centers in Narok North Sub-County. A structured and pretested questionnaire was used to collect data from 100 mothers. The multistage sampling method was used in this study to select the mothers who participated in the current study. The data were analysed descriptively. Additionally, Pearson’s chi-square, Kruskal-Wallis H, and logistic regression tests were conducted to determine the significance of the relationships and associations between the determinants and MCV uptake. A total of 69(69%) of the children (N =100) who had qualified for the first dose of measles vaccines (MCV1) had received the vaccines, while 31(31%) had not. Thirteen (26.5%) of the children (n = 49) who had qualified for the second dose of measles vaccine (MCV2) had received the vaccine, while 36(73.5%) did not. The significant maternal determinants of MCV uptake included; maternal age (p = .019) and maternal level of education (p = .030). The significant child’s determinants were birth order (p = .032) and place of birth (p = .001). The significant socioeconomic factors included; low socioeconomic background (p = .004) and cultural and religious issues (p = .003). The significant healthcare determinants included distance from the health facility (p = .020) and availability of vaccines in the health center (p = .000). Measles vaccine uptake was very low compared to the World Health Organization (WHO) recommended coverage rate of >95%. Thus, there is a need to provide health education and information to mothers or caregivers on measles vaccine uptake. Keywords: Vaccine, Vaccine Uptake, Measles

Factors Contributing to the Acceptability of Second Dose of Measles Vaccine among Children in Livingstone District, Zambia

Introduction: Measles is a viral disease that is a major public health problem in both developed and developing countries. It is a contagious disease resulting from infection with the measles virus and is still responsible for more than 100,000 deaths per year. Although vaccination is one of the most successful and cost-effective public health interventions to reduce mortality and morbidity, approximately 1.4 million children worldwide die from vaccine-preventable diseases each year. In Zambia, MCV2 was 66% below WHO recommended target of 95%. This study therefore assessed the acceptability of second dose measles vaccination services among caretakers/mothers with children less than two years of age in Livingstone, Zambia. Methods: The study used analytical cross-sectional study design. A logistic regression analysis was performed to identify factors associated with acceptability of the second dose of measles vaccine. A semi structured questionnaire was administered to collect data on socio demographic characteristics and factors related to acceptability of the second dose of measles vaccine. SPSS version 26.0 was used for descriptive and inferential analysis at 5% level of significance. Results: There was no statistically significant difference in acceptability of the second dose of measles vaccine by gender, marital status, type of employment, income level, socio-cultural and traditional beliefs, and education level. However, there was a statistically significant difference in acceptability of the second dose of measles vaccine by knowledge level of second dose of measles vaccine. A Chi square test result indicated that second dose acceptability was higher with less children than that of respondents with many children (χ2(5) = 15.3, p and knowledge levels (χ2(2) = 14.8, p Changes in knowledge level from medium to high reduced the odds of second dose measles vaccine acceptability. Furthermore, this study showed that acceptance of the second measles vaccination increased from mothers/caretakers with low knowledge (3.6%) to medium knowledge (13.3%) and finally high knowledge (83.1%). Conclusion: Tailored messaging to increase knowledge among mothers and caregivers on the importance of the second dose of measles vaccine is critical in improving acceptability. Therefore, the researchers recommend that the health providers should continue to raise awareness associated with the low acceptability of the second dose of measles vaccine and improve on child preventable diseases such as measles.

Factors Determining the Overlap between Recipients of the First and Second Dose of Measles Vaccine in 19 Studies

Factors Determining the Overlap between Recipients of the First and Second Dose of Measles Vaccine in 19 Studies

Missed Opportunities for Vaccination and Associated Factors among Children Attending Primary Health Care Facilities in Cape Town, South Africa: A Pre-Intervention Multilevel Analysis.

Despite the substantial efforts at ensuring universal access to routine immunisation services among children in South Africa, major gaps in immunisation coverage remain. This study assessed the magnitude of missed opportunities for vaccination (MOV) and associated factors among children aged 0–23 months attending primary health care (PHC) facilities in Cape Town. We used multilevel binomial logistic regression models to explore individual and contextual factors associated with MOV, with children aged 0–23 months at Level 1, nested within PHC facilities (Level 2). A total of 674 children and their caregivers were enrolled. MOV prevalence was 14.1%, ranging from 9.1% to 18.9% across sub-districts. Dose-specific MOV prevalence was highest for the second dose of measles vaccine (9.5%) and lowest for the first dose of rotavirus vaccine (0.6%). The likelihood of a child experiencing MOV was significantly associated with caregivers’ low level of education (Odds ratio (OR) = 3.53, 95% credible interval (CrI): 1.13–11.03), recent receipt of immunisation messages (OR = 0.46, 95%CrI: 0.25–0.87), shared immunisation decision making by both parents (OR = 0.21, 95%CrI: 0.07–0.62) and health facility staff number (OR = 0.18, 95%CrI: 0.06–0.61). The burden of MOV among children in Cape Town is influenced by individual and contextual factors, which provide important opportunities for quality improvement and broader strategies to improve routine immunisation service delivery.

The Effect of a Second Dose of Measles Vaccine at 18 Months of Age on Nonaccidental Deaths and Hospital Admissions in Guinea-Bissau: Interim Analysis of a Randomized Controlled Trial.

The world is set on the eradication of measles. Continuation of the measles vaccine (MV) after eradication could still reduce morbidity because the MV has so-called beneficial nonspecific effects. We evaluated the effect of a "booster" dose of the MV on overall severe morbidity. We conducted a randomized controlled trial among children aged 17.5 to 48 months in Guinea-Bissau, where the MV is recommended only at 9 months of age. At the time of this interim analysis, 3164 children had been allocated 1:1 to a second dose of measles vaccine (MV2) at 18 months of age or to no vaccine. Severe morbidity (a composite outcome of nonaccidental deaths and hospital admissions) rate ratios (SMRRs) were calculated by Cox regression analysis censored for national oral polio vaccine (OPV) campaigns. There were no measles cases during the trial period. There were 43 nonaccidental deaths or hospital admissions during follow-up. Severe morbidity was 2.6 per 100 person-years in the MV2 group and 3.6 per 100 person-years among controls; hence, the estimated effect of MV2 on severe morbidity was 28% (SMRR, 0.72; 95% confidence interval [CI], .38-1.38). At 12 months of follow-up, the number needed to treat to prevent 1 severe morbidity event was 137 children. After OPV campaigns, the estimated effect of MV2 was reduced to 9% (SMRR, 0.91; 95% CI, .46-1.81). MV2 may reduce nonmeasles severe morbidity by 28% (-38% to 62%), although this did not achieve statistical significance in this study. If significant in higher powered studies, this has major implications for child health, even after measles eradication. NCT02943681.

Access, demand, and utilization of childhood immunization services: A cross-sectional household survey in Western Area Urban district, Sierra Leone, 2019.

BackgroundUrban childhood immunization programs face unique challenges in access, utilization, and demand due to frequent population movement between and within localities, sprawling informal settlements, and population heterogeneity. We conducted a cross-sectional household survey in the Western Area Urban district, Sierra Leone, stratified by slums and non-slums as defined by the United Nations Development Program.MethodsBased on data from child vaccination cards, weighted vaccination coverage was estimated from 450 children aged 12-36 months (household response rate = 83%). Interviews with 444 caregivers identified factors related to accessing routine immunization services. Factors associated with coverage in bivariate analyses were examined in multivariate models using backward stepwise procedure.ResultsCoverage was similar in slums and non-slums for 3-doses of diphtheria-tetanus-pertussis-hepatitis B-Haemophilus influenzae type b (pentavalent) vaccine (86%, 92%) and second dose of measles vaccine (33%, 29%). In a multivariate logistic regression model, incomplete pentavalent vaccine coverage was associated with being second or later birth order (adjusted odds ratio (aOR) = 4.5 (95% confidence interval (CI) = 1.4-14.9), a household member not approving of childhood vaccinations (aOR = 7.55, 95% CI = 1.52-37.38), self-reported delay of child receiving recommended vaccinations (aOR = 4.8, 95% CI = 1.0-22.1), and living in a household made of natural or rudimentary materials (aOR = 3.5, 95% CI = 1.2-10.6). Overall, the majority (>70%) of caregivers reported occupation as petty trader and <50% reported receiving vaccination information via preferred communication sources.ConclusionsAlthough vaccination coverage in slums was similar to non-slums, study findings support the need for targeted interventions to improve coverage, especially for the second dose of measles vaccine to avoid large scale measles outbreaks. Strategies should focus on educating household members via preferred communication channels regarding the importance of receiving childhood vaccinations on time for all offspring, not just the first born. Vaccination coverage could be further improved by increasing accessibility through innovative strategies such as increasing the number of vaccination days and modifying hours.

Madagascar 2018-2019 measles outbreak response: main strategic areas.

Introductionon October 4th, 2018, a measles outbreak was declared in Madagascar. This study describes the outbreak response in terms of coordination, case management, vaccination response and epidemiological surveillance.Methodsdata were collected using a line list and vaccination tally sheet. Serum samples were collected within 30 days of rash onset for laboratory testing; confirmation was made by detection of measles immunoglobulin M antibody.Resultsfrom September 2018 to May 2019, a total of 146,277 measles cases were reported which included 1394 (1%) laboratory-confirmed cases and 144,883 (99%) epidemiological link-confirmed cases. The outbreak affected equally males (72,917 cases; 49.85%) and females (73,233 cases; 50.06%). The sex was not specified for 127 (0.09%) cases. Case fatality rate and attack rate were high among children less than 5 years. Responses interventions include effective coordination, free of charge case management, reactive vaccination, strengthened real-time surveillance, communication and community engagement and the revitalization of the routine immunization. Reactive vaccination was implemented in different phases. A total of 7,265,990 children aged from 6 months to 9 years were vaccinated. Post campaign survey coverage was 95%, 96% and 97% for phase 1, 2, 3 respectively.Conclusionelimination of measles will be challenging in Madagascar because of low routine immunization coverage and the absence of a second dose of measles vaccine in the routine immunization schedule.

Impact of COVID-19 pandemic on health system & Sustainable Development Goal 3.

Impact of COVID-19 pandemic on health system & Sustainable Development Goal 3.

Association between social capital and second dose of measles vaccination in Japan: Results from the A-CHILD study

Background and ObjectivesMeasles vaccination is important to prevent outbreak, and social capital can be an important preventive factor. However, there have been very few studies that investigated the association between social capital and measles vaccination, especially the second dose, which is more likely to be suboptimal. This study aimed to investigate the association between social capital and second dose of measles vaccine. MethodsData were derived from a population-based study of first-grade elementary school children (6–7 years old) in Adachi City, Tokyo. Caregivers were asked to complete a questionnaire, and 4291 of them provided a valid response (response rate: 80.1%). Among these 4291 valid responses, 69 responses were excluded since variables for social capital measures were missing, which resulted in analytic sample size of 4222. We analyzed the association between measles vaccination and social capital including social ties, social trust and mutual aid by multilevel logistic regression analysis with a random intercept model. ResultsAbout 8.9% of the children did not receive a second dose of measles-containing vaccines. After covariates adjustments, increase of one-standard-deviation of poor individual-level social ties showed 11% lower odds of receiving measles-containing vaccines (OR: 0.89, 95% CI: 0.80–0.99). By contrast, no significant association between community-level social ties and measles vaccination was found. Regarding social trust, no significant association between individual-level social trust and measles vaccination was found. However, increase of one-standard-deviation of poor community-level social trust showed 11% lower odds of receiving measles-containing vaccines (OR: 0.89, 95% CI: 0.79–0.998). There was no association between mutual aid and measles vaccination. ConclusionSocial ties and social trust were associated with second dose of measles vaccination. Fostering social capital may be effective in raising the low rate of second dose of measles vaccine.

Lessons learned from detecting and responding to recurrent measles outbreak in Liberia post Ebola-Epidemic 2016-2017.

IntroductionMeasles is an acute viral disease that remains endemic in much of sub-Sahara Africa, including Liberia. The 2014 Ebola epidemic disrupted an already fragile health system contributing to low uptake of immunization services, population immunity remained low thus facilitating recurrent outbreaks of measles in Liberia. We describe lessons learnt from detecting and responding to recurrent outbreaks of measles two years post the 2014 Ebola epidemic in Liberia.MethodsWe conducted a descriptive study using the findings from Integrated Diseases Surveillance and Response (IDSR) 15 counties, National Public Health Institute of Liberia (NPHIL), National Public Health Reference Laboratory (NPHRL) and District Health Information Software (DIHS2) data conducted from October to December, 2017. We perused the outbreaks line lists and other key documents submitted by the counties to the national level from January 2016 to December 2017.ResultsFrom January 2016 to December 2017, 2,954 suspected cases of measles were reported through IDSR. Four hundred sixty-seven (467) were laboratory confirmed (IgM-positive), 776 epidemiologically linked, 574 clinically confirmed, and 1,137 discarded (IgM-negative). Nine deaths out of 1817 cases were reported, a case fatality rate of 0.5%; 49% were children below the age of 5 years. Twenty-two percent (405/1817) of the confirmed cases were vaccinated while the vaccination status of 55% (994/1817) was unknown.ConclusionRevitalization of IDSR contributed to increased detection and reporting of suspected cases of measles thus facilitating early identification and response to outbreaks. Priority needs to be given to increasing the uptake of routine immunization services, introducing a second dose of measles vaccine in the routine immunization program and conducting a high-quality supplementary measles immunization campaign for age group 1 to 10 years to provide protection for a huge cohort of susceptible.

Measles vaccination coverage, determinants of delayed vaccination and reasons for non-vaccination among children aged 24\u201335\u2009months in Zhejiang province, China

BackgroundThis study was aimed to assess the coverage of two doses of measles vaccine and identify the determinants of the delayed vaccination.MethodsA cluster survey among 1386 children aged 24–35 months was conducted. Characteristics on demographic and socio-economic and vaccination records was collected. The overall coverage was defined as the proportion of children receiving the first dose of measles vaccination and the second dose of measles vaccination by 24 months of age. The age-appropriate coverage was defined as the proportion of children receiving the measles vaccine doses within one month after its relevant due date. Timeliness was evaluated with the Kaplan-Meier analysis. Cox proportional hazard regression was adopted to identify determinants of the delayed vaccination.ResultsThe overall coverage was 96.9% for the first dose of measles vaccine and 93.9% for the second dose of measles vaccine. The age-appropriate coverage of the first and the second dose of measles vaccine was 76.6 and 68.2%, respectively. Household having more than one child, non-local children were associated with the delayed vaccination for the first and the second dose of measles vaccine. Children delivered at home, younger mothers, low maternal education background, mothers with a fixed job, and low household income were associated with the delayed vaccination for the second dose of measles vaccine.ConclusionsThe coverage of measles vaccine had been improved for both the first and the second dose, while the timeliness still needed improvement. We suggested the policy-makers pay more attention to the reasons for non-vaccination and determinants of delayed vaccination when planning efforts to ensure the high age-appropriate coverage of measles vaccination.

Status of Measles Elimination in Eleven Countries with High Routine Immunisation Coverage in The WHO African Region

Measles elimination is defined as the absence of endemic measles virus transmission in a defined geographic area for at least 12 months in the presence of a well-performing surveillance system. The WHO framework for verification of measles elimination indicates that the achievement of measles and/or rubella elimination should be verified for individual countries. We identified 11 high performing countries based on their first dose measles vaccination coverage, and looked at their performance across the various programmatic parameters, to see if they are ready to undertake the verification of measles elimination. We identified 11 countries with >90% measles first dose coverage for the most recent 5 years according to the WHO UNICEF estimates of national immunisation coverage. We analysed vaccination coverage and surveillance performance in these countries. Algeria, Botswana, Gambia, Mauritius, Rwanda, Seychelles have maintained measles first dose (MCV1) coverage of 95% or more since 2011. In 2015, only Algeria, Cape Verde and Seychelles had coverage of 95% or more for the second dose of measles vaccine (MCV2). Of the 22 supplemental immunisation activities (SIAs) among the 11 countries, only 6 had administrative coverage of less than 95%. Only Rwanda and Lesotho attained the case-based surveillance performance targets in all the five years. Despite their high routine first dose measles immunisation coverage, all of the 11 countries have some program gaps indicating that they do not meet all the criteria to undergo verification of elimination at this point. It is recommended for these countries to set up national verification committees as per the WHO framework for verification of measles elimination, in order to initiate the documentation and monitoring of progress, and to address programmatic gaps in the coming years.

Visiting health centers as a risk factor for measles transmission: Kamwenge District, Uganda, April – July 2015

Uganda has been implementing a one-dose measles vaccination at age 9 months in its national EPI schedule. On 27 April 2015, a measles outbreak, which was confirmed by serum positivity in several patients, occurred in Kamwenge District. Since then, the number of reported measles patients has increased despite the implementation of measures to control the outbreak by the local government. We investigated this outbreak to identify the risk factors for measles transmission, estimate vaccination coverage, determine vaccine effectiveness, and recommend control measures. We defined a probable case as onset in a Kamwenge District resident of fever and generalized rash from 16 April 2015 onward with ≥ 1 of the following: coryza, conjunctivitis, or cough. A confirmed case was a probable case with positive measles-specific IgM in patient serum. For case-finding we reviewed medical records and found patients in the community with the help of the village health team. We determined vaccination histories by vaccination cards or interviews. In a case-control study, we compared the exposure histories of 50 probable case-persons with 200 asymptomatic control-persons during case-persons’ exposure period (i.e., between minimum and maximum incubation). We matched case- and control-persons by age and residence village. We estimated vaccination coverage for children aged ≤ 2 years based on the percent of control-children vaccinated. We identified 213 probable/confirmed cases from 3 affected sub-counties (attack rate = 5.1/10,000). The epidemic curve showed sustained community transmission. The case-control study showed that 42% (21/50) of case-persons and 12% (23/200) of control-persons visited health centers during case-persons’ exposure period (AORM-H = 6.1; 95% CI = 2.7-14). Vaccination coverage among children aged ≤2 years was 58% (95% CI = 47-68%). The vaccine effectiveness was 80% (95% CI=35-94%). We found that all health centers were crowded, with no triaging system to separate suspect measles patients from patients with other illnesses. Exposures to measles patients at crowded health centers, low vaccination coverage, and suboptimal vaccine effectiveness facilitated measles transmission in this outbreak. We recommended an emergency immunization campaign targeting young children, triaging and isolating suspect measles patients at health centers, and introducing a second dose of measles vaccine in the immunization schedule.

Assessing the cost-effectiveness of different measles vaccination strategies for children in the Democratic Republic of Congo.

One of the goals of the Global Measles and Rubella Strategic Plan is the reduction in global measles mortality, with high measles vaccination coverage as one of its core components. While measles mortality has been reduced more than 79%, the disease remains a major cause of childhood vaccine preventable disease burden globally. Measles immunization requires a two-dose schedule and only countries with strong, stable immunization programs can rely on routine services to deliver the second dose. In the Democratic Republic of Congo (DRC), weak health infrastructure and lack of provision of the second dose of measles vaccine necessitates the use of supplementary immunization activities (SIAs) to administer the second dose. We modeled three vaccination strategies using an age-structured SIR (Susceptible-Infectious-Recovered) model to simulate natural measles dynamics along with the effect of immunization. We compared the cost-effectiveness of two different strategies for the second dose of Measles Containing Vaccine (MCV) to one dose of MCV through routine immunization services over a 15-year time period for a hypothetical birth cohort of 3 million children. Compared to strategy 1 (MCV1 only), strategy 2 (MCV2 by SIA) would prevent a total of 5,808,750 measles cases, 156,836 measles-related deaths and save U.S. $199 million. Compared to strategy 1, strategy 3 (MCV2 by RI) would prevent a total of 13,232,250 measles cases, 166,475 measles-related deaths and save U.S. $408 million. Vaccination recommendations should be tailored to each country, offering a framework where countries can adapt to local epidemiological and economical circumstances in the context of other health priorities. Our results reflect the synergistic effect of two doses of MCV and demonstrate that the most cost-effective approach to measles vaccination in DRC is to incorporate the second dose of MCV in the RI schedule provided that high enough coverage can be achieved.

Determinants of contraceptive use among postpartum women in a county hospital in rural KENYA

BackgroundThere is a high unmet need for limiting and spacing child births during the postpartum period. Given the consequences of closely spaced births, and the benefits of longer pregnancy intervals, targeted activities are needed to reach this population of postpartum women. Our objective was to establish the determinants of contraceptive uptake among postpartum women in a county referral hospital in rural Kenya.MethodsSample was taken based on a mixed method approach that included both quantitative and qualitative methods of data collection. Postpartum women who had brought their children for the second dose of measles vaccine between 18 and 24 months were sampled Participants were interviewed using structured questionnaires, data was collected about their socio-demographic characteristics, fertility, knowledge, use, and access to contraceptives. Chi square tests were used to determine the relationship between uptake of postpartum family planning and: socio demographic characteristics, contraceptive knowledge, use access and fertility. Qualitative data collection included focus group discussions (FDGs) with mothers and in-depth interviews with service providers Information was obtained from mothers’ regarding their perceptions on family planning methods, use, availability, access and barriers to uptake and key informants’ views on family planning counseling practices and barriers to uptake of family planningResultsMore than three quarters (86.3%) of women used contraceptives within 1 year of delivery, with government facilities being the most common source. There was a significant association (p ≤ 0.05) between uptake of postpartum family planning and lower age, being married, higher education level, being employed and getting contraceptives at a health facility. One third of women expressing no intention of having additional children were not on contraceptives. In focus group discussions women perceived that the quality of services offered at the public facilities was relatively good because they felt that they were adequately counseled, as opposed to local chemist shops where they perceived the staff was not experienced.ConclusionContraceptive uptake was high among postpartum women, who desired to procure contraceptives at health facilities. However, there was unmet need for contraceptives among women who desired no more children. Government health facility stock outs represent a missed opportunity to get family planning methods, especially long acting reversible contraceptives, to postpartum women.

Status of New Vaccine Introduction - Worldwide, September 2016.

Since the global Expanded Program on Immunization (EPI) was launched in 1974, vaccination against six diseases (tuberculosis, polio, diphtheria, tetanus, pertussis, and measles) has prevented millions of deaths and disabilities (1). Significant advances have been made in the development and introduction of vaccines, and licensed vaccines are now available to prevent 25 diseases (2,3). Historically, new vaccines only became available in low-income and middle-income countries decades after being introduced in high-income countries. However, with the support of global partners, including the World Health Organization (WHO) and the United Nations Children's Fund, which assist with vaccine prequalification and procurement, as well as Gavi, the Vaccine Alliance (Gavi) (4), which provides funding and shapes vaccine markets through forecasting and assurances of demand in low-income countries in exchange for lower vaccine prices, vaccines are now introduced more rapidly. Based on data compiled in the WHO Immunization Vaccines and Biologicals Database* (5), this report describes the current status of introduction of Haemophilus influenzae type b (Hib), hepatitis B, pneumococcal conjugate, rotavirus, human papillomavirus, and rubella vaccines, and the second dose of measles vaccine. As of September 2016, a total of 191 (99%) of 194 WHO member countries had introduced Hib vaccine, 190 (98%) had introduced hepatitis B vaccine, 132 (68%) had introduced pneumococcal conjugate vaccine (PCV), and 86 (44%) had introduced rotavirus vaccine into infant vaccination schedules. Human papillomavirus vaccine (HPV) had been introduced in 67 (35%) countries, primarily targeted for routine use in adolescent girls. A second dose of measles-containing vaccine (MCV2) had been introduced in 161 (83%) countries, and rubella vaccine had been introduced in 149 (77%). These efforts support the commitment outlined in the Global Vaccine Action Plan (GVAP), 2011-2020 (2), endorsed by the World Health Assembly in 2012, to extend the full benefits of immunization to all persons.

Optimal vaccine schedules to maintain measles elimination with a two-dose routine policy.

Measles was eliminated in the Americas in 2002 by a combination of routine immunizations and supplementary immunization activities. Recent outbreaks underscore the importance of reconsidering vaccine policy in order to maintain elimination. We constructed an age-structured dynamical model for the distribution of immunity in a population with routine immunization and without disease, and analysed the steady state for an idealized age structure and for real age structures of countries in the Americas. We compared the level of immunity maintained by current policy in these countries to the level maintainable by an optimal policy. The optimal age target for the first routine dose of measles vaccine depends on the timing and coverage of both doses. Similarly, the optimal age target for the second dose of measles vaccine depends on the timing and coverage of the first dose. The age targets for the first and second doses of measles vaccine should be adjusted for the post-elimination era, by specifically accounting for current context, including realized coverage of both doses, and altered maternal immunity. Doing so can greatly improve the proportion immune within a population, and therefore the chances of maintaining measles elimination, without changing coverage.

Comparison of neutralizing antibody titers against outbreak-associated measles genotypes (D4, H1 and B3) in Iran.

Despite the accessibility of a promising vaccine, outbreaks of the measles virus (MV) take place even in well-vaccinated populations. D4, H1 and B3 genotypes have been detected regularly in different regions of Iran. These observations highlight the necessity of evaluating the protective efficacy of the vaccine against currently circulating MV genotypes during the elimination phase. A focus reduction neutralization test has been developed to measure the neutralizing antibodies against different genotypes of MV, such as H1, D4, B3 and vaccine strain (A), in children after second doses of measles vaccine. The geometric mean titer (GMT) rates of the sera against D4, H1, B3 and A genotypes were 95.9, 90.5, 32.0 and 76.1, respectively. Low GMTs of antibody against the B3 genotype compared with the other genotypes were indicated. Based on the current study results, the MV antibody titers in the sera of vaccinated cases are sufficient to neutralize all circulating genotypes in Iran; however, neutralizing antibody titers were lower for the B3 genotype than for the H1, D4 and A genotypes. The heterogeneous nature of MV, for instance the nucleotide sequence diversity between different strains, necessitates the evaluation of the protective efficacy of the vaccine against measles B3 genotype in countries where this virus has been the most commonly identified circulating genotype.