Global Vaccination Coverage Research Articles

Economic and Behavioral Influencers of Vaccination and Antimicrobial Use.

Despite vast improvements in global vaccination coverage during the last decade, there is a growing trend in vaccine hesitancy and/or refusal globally. This has implications for the acceptance and coverage of a potential vaccine against COVID-19. In the United States, the number of children exempt from vaccination for “philosophical belief-based” non-medical reasons increased in 12 of the 18 states that allowed this policy from 2009 to 2017 (1). Meanwhile, the overuse and misuse of antibiotics, especially in young children, have led to increasing rates of drug resistance that threaten our ability to treat infectious diseases. Vaccine hesitancy and antibiotic overuse exist side-by-side in the same population of young children, and it is unclear why one modality (antibiotics) is universally seen as safe and effective, while the other (vaccines) is seen as potentially hazardous by some. In this review, we consider the drivers shaping the use of vaccines and antibiotics in the context of three factors: individual incentives, risk perceptions, and social norms and group dynamics. We illustrate how these factors contribute to the societal and individual costs of vaccine underuse and antimicrobial overuse. Ultimately, we seek to understand these factors that are at the nexus of infectious disease epidemiology and social science to inform policy-making.

Vaccination perception and coverage among healthcare students in France in 2019

BackgroundVaccine hesitancy in healthcare workers has been increasing especially in France while they are the cornerstone of vaccination programs. Greater understanding of healthcare students (HCS) vaccine knowledge, attitudes and beliefs is necessary to provide an adequate vaccination education to better equip them to promote vaccination in their future careers. The aim of this study was to assess vaccination perception (VP) (perception of benefits and risks of vaccines) and its impact on vaccination coverage (VC) for mandatory and recommended vaccines among HCS.MethodsA standardized, anonymous self-reporting electronic questionnaire was prospectively sent to HCS (medicine, nursing, pharmacy, midwifery, physiotherapy students and 1st year of health sciences students) of Normandy University in France between 18/03/2019 and 8/04/2019. VP was evaluated with questions regarding vaccination hesitancy, safety of vaccine and the benefit/risk balance of vaccination. Global VC (GVC) was defined as being vaccinated according to the mandatory and/or recommended vaccination schedule by national French law in 2018.Results542 HCS took part in this survey. VC was high for mandatory (diphtheriae, poliomyelitis, tetanus 93.5%, hepatitis B virus 88.6%) and even most of recommended vaccinations (measles 95%, pertussis 88.2%). Global VC (40.4%) was not statistically different between HCS except for 1st year health sciences students who were less vaccinated (25.6%). Regarding VP, 97.8% of HCS thought that vaccine are effective. When vaccine safety and level of vaccine hesitancy were assessed (on a 0–10 scale, 0: not safe or not hesitant and 10: completely safe and strongly hesitant for vaccine), 91% of respondents stated that vaccine safety is ≥7 and in 80% the vaccine hesitancy was < 3. There was no difference among student categories. 80.6% of HCS recommended all vaccines but only 52% agreed that flu vaccination should be mandatory for HCS. In the multivariate analysis, being a 1st year health care sciences student was associated with a lower GVC (OR 95% CI = 2 [1.2–3.3], p = 0.004) than being a medical student.ConclusionHCS perceived vaccine as effective and secure. Despite the good perception of vaccines, less than half HCS are well vaccinated.

Mulberry leaf polysaccharide supplementation contributes to enhancing the respiratory mucosal barrier immune response in Newcastle disease virus–vaccinated chicks

Despite high global vaccination coverage, Newcastle disease (ND) remains a constant threat to poultry producers owing to low antibody levels. Given the respiratory mucosa is the important site for Newcastle disease virus (NDV) vaccination, enhancing respiratory mucosal immunity may help control ND. Our previous study showed that mulberry leaf polysaccharide (MLP) is very promising in delivering a robust balanced immune response, but the effects of it on respiratory immunity in chicks are unknown. In this study, we evaluated the potential of MLP to activate respiratory mucosal immunity and revealed the possible mechanism of MLP as an immunopotentiator for ND vaccines. Chicks were randomly divided into 5 groups: blank control, vaccination control (VC), and low-, middle-, and high-dose MLP (MLP-L, MLP-M, and MLP-H) (n = 30). The serum results of humoral and cell-mediated immune responses showed significant increases in NDV hemagglutination inhibition antibody titer, IgG and IgA antibody levels, and the T-lymphocyte population in the MLP-M group compared with the VC group. Validation of results also indicated remarkable increases in tracheal antibody-mediated immunity and a mucosal immune response in the MLP-M group. Furthermore, the upregulation of TLR7 revealed a possible mechanism. Our findings provided evidence to consider MLP as a potential mucosal vaccine adjuvant candidate against ND in chickens.

Multiple Introductions and Predominance of Rotavirus Group A Genotype G3P[8] in Kilifi, Coastal Kenya, 4 Years after Nationwide Vaccine Introduction.

Globally, rotavirus group A (RVA) remains a major cause of severe childhood diarrhea, despite the use of vaccines in more than 100 countries. RVA sequencing for local outbreaks facilitates investigation into strain composition, origins, spread, and vaccine failure. In 2018, we collected 248 stool samples from children aged less than 13 years admitted with diarrheal illness to Kilifi County Hospital, coastal Kenya. Antigen screening detected RVA in 55 samples (22.2%). Of these, VP7 (G) and VP4 (P) segments were successfully sequenced in 48 (87.3%) and phylogenetic analysis based on the VP7 sequences identified seven genetic clusters with six different GP combinations: G3P[8], G1P[8], G2P[4], G2P[8], G9P[8] and G12P[8]. The G3P[8] strains predominated the season (n = 37, 67.2%) and comprised three distinct G3 genetic clusters that fell within Lineage I and IX (the latter also known as equine-like G3 Lineage). Both the two G3 lineages have been recently detected in several countries. Our study is the first to document African children infected with G3 Lineage IX. These data highlight the global nature of RVA transmission and the importance of increasing global rotavirus vaccine coverage.

Routine Vaccination Coverage - Worldwide, 2019.

Endorsed by the World Health Assembly in 2020, the Immunization Agenda 2030 strives to reduce morbidity and mortality from vaccine-preventable diseases across the life course (1). This report, which updates previous reports (2), presents global, regional,* and national vaccination coverage estimates and trends as of 2019 and describes the number of surviving infants who did not receive the first dose of diphtheria and tetanus toxoids and pertussis-containing vaccine (DTP1) during the first year of life (i.e., zero-dose children), which serves as a proxy for children with poor access to immunization and other health services. Global estimates of coverage with the third dose of DTP (DTP3), the first dose of measles-containing vaccine (MCV1), and the third dose of polio vaccine (Pol3) ranged from 84% to 86% during 2010-2019. Worldwide, 19.7 million children (15%) were not vaccinated with DTP3 in 2019, 13.8 million (70%) of whom were zero-dose children. During 2010-2019, the number of zero-dose children increased in the African, Americas, and Western Pacific regions. Global coverage with the second MCV dose (MCV2) increased from 42% in 2010 to 71% in 2019. During 2010-2019, global coverage with underused vaccines increased for the completed series of rotavirus vaccine (rota), pneumococcal conjugate vaccine (PCV), rubella-containing vaccine (RCV), Haemophilus influenzae type b vaccine (Hib), hepatitis B vaccine (HepB), and human papillomavirus vaccine (HPV). Achieving universal coverage with all recommended vaccines will require tailored, context-specific strategies to reach communities with substantial proportions of zero-dose and incompletely vaccinated children, particularly those in remote rural, urban poor, and conflict-affected communities (3).

Flu vaccination coverage among healthcare workers: a comparison between 2018 and 2019 campaigns

Abstract Background In Italy, recommended annual influenza vaccination is free to healthcare workers (HCWs) to prevent flu spread. No official data are available on HCWs' vaccination coverage (VC), which minimum target is set at 75%. Aim of this study is to compare 2019-20 and 2018-19 flu vaccination coverage in order to evaluate last year campaign effectiveness. Methods 2019-20 flu vaccination campaign efforts at Udine Hospital (Italy) were improved with the aid of public health residents to tackle HCWs convenience concerns. From October 29th to December 5th 2019, dedicated areas and days were increased, informative course about influenza vaccination (efficacy, benefits and safety) toward HCWs were conducted. Data about HCWs getting their flu shot within the hospital were traced and analyzed, grouping different categories. Results During 2019-20 flu season, vaccinated HCWs were 29.1% (1,169/4,012), while they were 22.7% (955/4,203) in 2018-19 (p &amp;lt; 0.0001). The 2019-20 campaign resulted to be effective among doctors (45.0% vs 38.4%; p = 0.0132), residents (52.4% vs 40.7%; p = 0.0003) and nurses (24.1% vs 17.3%; p &amp;lt; 0.0001). The less compliant category was midwives, who maintained the worse vaccination coverage in both seasons (20.4% and 24.1%; p = 0.6555). Regarding other HCWs in 2019-20, 18.6% were vaccinated (in 2018-19 14.0%, p = 0.002). Conclusions A significant improvement in vaccination coverage during 2019-20 flu season was reached by the specific vaccination campaign for all categories except midwives. Despite this, the global vaccination coverage is still far from the desired target and more must be done to fill this gap. Evidence of HCWs categories for which this intervention was more effective, could be useful in planning next flu vaccination strategies. Key messages Continuous efforts made by public health professionals in promoting flu vaccination show their effect on healthcare workers flu shot adherence. A planned vaccination agenda and educative course about influenza infection and benefits of vaccination, seem to be good strategies to improve vaccination coverage.

Impact of a decision-aid tool on influenza vaccine coverage among HCW in two French hospitals: A cluster-randomized trial

IntroductionNosocomial outbreaks of seasonal influenza are frequent, and vaccination is largely recommended for healthcare workers (HCWs). Vaccine coverage in French HCWs does not exceed 20%. Decision-aids (DA) are potential useful interventions to increase vaccine coverage (VC). Our aim was to evaluate the impact of a DA on HCWs influenza vaccine coverage. Material and methodsProspective cluster-randomized trial conducted in 83 departments in two public hospitals (a teaching and a non-teaching hospital) during the 2018–2019 flu season.Distribution of the DA and of questionnaire about decisional conflict and knowledge in the departments randomized in the intervention group. ResultsA total number of 3 547 HCWs were concerned by the study (1 953 in the intervention group, 1 594 in the control group). Global VC was 35.6% during the 2018–2019 season, instead of 23.6% in the 2017–2018 season (p < 0.005). During the 2018–2019 season, VC was 31% (95% CI 28.7–33.3) in the control group and 38.7% (95% CI 36.5–40.9) in the intervention group (p < 0.005). Among the 158 HCWs exposed to the DA who answered the survey, 51.3% had no decisional conflict. HCWs without decisional conflict were more prone to get vaccinated before flu season. ConclusionThe use of the DA was associated with a 25% relative increase in VC among HCWs against seasonal influenza. This modest increase remained far from the WHO 75% target, but may have reduced the number of nosocomial. Multi-component interventions are needed to increase VC in HCWs.

Overview of Vaccine Drug Delivery System

Until the 20th century, infectious diseases were the leading cause of death and disability worldwide, and this is still the case in much of the developing world. Immunisation has played a central role in radically reducing the incidence of many dangerous diseases, and some diseases have been wiped out entirely (e.g. smallpox). This article presents the World Health Organization’s (WHO) recommendations on the use of various vaccines. Vaccines prevent an estimated two –three million deaths worldwide every year. But, a further 2 million lives could be saved annually with better global vaccine coverage. Vaccines prevent an estimated two – three million deaths worldwide every year. But, a further 2 million lives could be saved annually with better global vaccine coverage. The purpose of vaccination is to produce immunity. Vaccines contain the same germs that cause disease. (For example, measles vaccine contains measles virus.) But they have been either killed or weakened. A vaccine provides a conducted exposure to a pathogen, training and encourage the immune system so it can fight that disease quickly and effectively in future. The national Vaccine Injury Compensation Program covers routine vaccines for children (against a total of 16 diseases). Vaccines are safe and effective. Because vaccines are given to millions of wholesome people. Vaccines have one of the greatest impacts on public good health. The prevention of disease has had an enormous impact on commercial development by limiting the costs of curative care and saving billions of dollars in countries where diseases have been well controlled or eliminated.

Opinions and Knowledge of Parents Regarding Preventive Vaccinations of Children and Causes of Reluctance toward Preventive Vaccinations.

Background: Despite the stability of global vaccination coverage, over 19 million children worldwide do not currently receive basic vaccines. Over the past several years, there has been a dramatic drop in the number of vaccinated children worldwide. The implementation of the vaccination program and the scope of protection depend on the parents or legal guardians, who decide whether to vaccinate their child or not. Studies were conducted to assess parents’ knowledge, attitudes, and beliefs about vaccines, as well as the role of healthcare providers in parents’ decisions. Methods: A population survey was conducted in 2018–2019. Parents or legal guardians of the children were invited to participate in the study during their visits to the clinic for healthy or sick children. The method used in the research was a diagnostic survey. Results: According to the conducted research, men and women constituted 45% and 55% of participants, respectively. The average age of men was 44, while, for women, it was 41. Internal research showed that as much as 71% of parents declared the need for vaccination, although 41% of parents vaccinated their children according to the vaccination calendar. The most frequently mentioned concerns included the possibility of adverse vaccination reactions (22%), the occurrence of autism (7%), and child death (6%). General practitioners had, by far, the greatest impact on the use of protective vaccination in children (73% women and 80% men), although there were cases of discouraging the performance of compulsory vaccinations (41%), and mentioning a doctor (38%) or nurse (3%). Conclusions: Modifiable determinants of the negative attitude toward vaccinations are caused mainly by the lack of knowledge. These obstacles in vaccinations can be overcome by improving health education in terms of the vaccination program.

WITHDRAWN: Is global BCG vaccination coverage relevant to the progression of SARS-CoV-2 pandemic?

The lower than expected number of SARS-CoV-2 cases in countries with fragile health systems is puzzling. Herein, we hypothesize that BCG vaccination policies adopted by different countries might influence the SARS-CoV-2 transmission patterns and/or COVID-19 associated morbidity and mortality through the vaccine’s capacity to confer heterologous protection. We also postulate that until a specific vaccine is developed, SARS-CoV-2 vulnerable populations could be immunized with BCG vaccines to attain heterologous nonspecific protection from the new coronavirus.

Global BCG Vaccination Coverage versus Cases and Mortality in the SARS-CoV-2 Pandemic

Global BCG Vaccination Coverage versus Cases and Mortality in the SARS-CoV-2 Pandemic

Using Data to Keep Vaccines Cold in Kenya: Remote Temperature Monitoring with Data Review Teams for Vaccine Management.

Global vaccination coverage rates have remained around 85% for the past several years. Increasing immunization coverage rates requires an effective cold chain to maintain vaccine potency. Remote temperature monitoring (RTM) technology for vaccine refrigerators has shown promise for improving the ability of supply systems to maintain optimal temperature conditions to ensure potent vaccines reach the end users. A pilot study of RTM technology and data use teams was implemented in 36 study sites in Kenya. Data were collected at baseline and endline points over a 3-month baseline and 7-month implementation period. Data included 44 qualitative interviews, process logs, meeting minutes from data use team meetings, and quantitative temperature and power data from the RTM devices. The ability of cold chain equipment to maintain World Health Organization-recommended temperatures in study sites improved markedly between the baseline and implementation periods, resulting in an improvement in total time spent in the correct range from 83.9% in the baseline period to 90.9% in the intervention period and an improvement in time spent in the too cold range from 6.5% to 1.5%. Friedman tests revealed that differences in time spent in the correct range and time spent in the too cold range during the course of the study were statistically significant (P<.001 and P=.04, respectively). Qualitative and quantitative data suggest that this improvement was due to a combination of improved responsiveness to temperature excursions at the facility level, resulting from SMS alarms for temperature excursion periods, and improved ability at the management level to recognize and address recurring problems. The combination of using RTM technology with a structured data review process by a management team is a promising approach for improving cold chain outcomes. Future research examining the added value of each of the technological and behavioral components separately is needed.

Early Protection against Pertussis Induced by Live Attenuated Bordetella pertussis BPZE1 Depends on TLR4.

Pertussis is a severe respiratory disease mainly caused by Bordetella pertussis Despite wide global vaccination coverage with efficacious pertussis vaccines, it remains one of the least well-controlled vaccine-preventable diseases, illustrating the shortcomings of the current vaccines. We have developed the live attenuated nasal pertussis vaccine BPZE1, currently undergoing clinical evaluation in human phase 2 trials. We have previously shown that in mice, BPZE1 provides strong and long-lasting protection against B. pertussis challenge by inducing potent Ab and T cell responses as well as secretory IgA and IL-17-producing resident memory T lymphocytes in the nasal cavity. In this study, we show that BPZE1 induces protection in mice against B. pertussis within days after vaccination, at a time when Ab and T cell responses were not detectable. Early protection was independent of T and B cell responses, as demonstrated by the use of SCID mice. Instead, it was due to TLR4-dependent signaling through the MyD88-dependent pathway of the innate immune response, as demonstrated in experiments with TLR4-deficient and MyD88-knockout mice. TLR2-dependent signaling did not play a major role in early protection. In addition, this study also shows that even at high doses, BPZE1 is safe in the severely immunocompromised MyD88-deficient mice, whereas virulent B. pertussis caused a severe pathological condition and death in these mice, even at a low dose. Finally, coadministration of virulent B. pertussis with BPZE1 did not cause exacerbated outgrowth of the virulent strain, thereby adding to the safety profile of this live vaccine candidate.

New immunization strategies: adapting to global challenges.

Immunization has made an enormous contribution to global health. Global vaccination coverage has dramatically improved and mortality rates among children due to vaccine-preventable diseases have been significantly reduced since the creation of the Expanded Programme of Immunization in 1974, the formation of Gavi, the Vaccine Alliance, in 2000, and the development of the Global Vaccine Action Plan in 2012. However, challenges remain and persisting inequities in vaccine uptake contribute to the continued occurrence and outbreaks of vaccine-preventable diseases. Inequalities in immunization coverage by geography, urban-rural, and socio-economic status jeopardize the achievement of global immunization goals and call for renewed immunization strategies. These should take into account emerging opportunities for building better immunization systems and services, as well as the development of new vaccine products and delivery technologies. Such strategies need to achieve equity in vaccination coverage across and within countries. This will require the participation of communities, a better understanding of vaccine acceptance and hesitancy, the expansion of vaccination across the life course, approaches to improve immunization in middle-income countries, enhanced use of data and possible financial and non-financial incentives. Vaccines also have an important role to play in comprehensive disease control, including the fight against antimicrobial resistance. Lessons learned from disease eradication and elimination efforts of polio, measles and maternal and neonatal tetanus are instrumental in further enhancing global immunization strategies in line with the revised goals and targets of the new Immunization Agenda 2030, which is currently being developed.

Global Routine Vaccination Coverage, 2018.

Endorsed by the World Health Assembly in 2012, the Global Vaccine Action Plan 2011-2020 (GVAP) (1) calls on all countries to reach ≥90% national coverage with all vaccines in the country's national immunization schedule by 2020. Building on previous analyses (2) and using the World Health Organization (WHO) and United Nations Children's Fund (UNICEF) global vaccination coverage estimates as of 2018, this report presents global, regional, and national vaccination coverage estimates and trends, including vaccination dropout rates. According to these estimates, global coverage with the first dose of diphtheria and tetanus toxoids and pertussis-containing vaccine (DTP1) remained relatively unchanged from 2010 (89%) to 2018 (90%). Global coverage with the third DTP dose (DTP3) followed a similar global trend to that of DTP1, remaining relatively consistent from 2010 (84%) to 2018 (86%) (3). Globally, 19.4 million children (14%) were not fully vaccinated in 2018, and among them, 13.5 million (70%) did not receive any DTP doses. Overall, dropout rates from DTP1 to DTP3 decreased globally from 6% in 2010 to 4% in 2018. Global coverage with the first dose of measles-containing vaccine (MCV1) remained between 84% and 86% during 2010-2018. Among countries that offer a second MCV dose (MCV2) during the second year of life, coverage increased from 19% in 2007 to 54% in 2018; among countries offering MCV2 to older age groups (children aged 3-14 years), coverage also increased, from 36% in 2007 to 69% in 2018 (3). Globally, the estimated difference in coverage with MCV1 and MCV2 in 2018 was 17%. However, among new and underused vaccines, global coverage increased from 2007 to 2018 for completed series of rotavirus vaccine, pneumococcal conjugate vaccine (PCV), rubella vaccine, Haemophilus influenzae type b vaccine (Hib), and hepatitis B vaccine (HepB). To reach global vaccination coverage goals for vaccines recommended during childhood, adolescence, and adulthood, tailored strategies that address local determinants for incomplete vaccination are needed, including targeting hard-to-reach and hard-to-vaccinate populations.

Effect of mobile phone text messaging for improving the uptake of influenza vaccination in patients with rare diseases

ObjectivesInfluenza vaccine is recommended in some chronic medical conditions, including several rare diseases. The objectives of the study were to assess the effect of text message reminders on influenza vaccination uptake of patients with selected rare diseases and delayed vaccination, and to describe their characteristics. MethodsQuasi-experimental pre-post intervention study performed along the 2016 influenza vaccination campaign in the Autonomous Community of Madrid. Unvaccinated patients diagnosed with a selected rare disease were targeted for intervention. SMS were sent to them at least one month after the beginning of the campaign, in four consecutive weeks. Those with no mobile phones available or no certainty of message reception, were assigned as controls. The association between the reception of the SMS and vaccination uptake was assessed using multiple poisson regression models. ResultsOf 69.040 patients with delayed vaccination, 87.2% received an SMS reminder in the asigned contact mobile telephone. Global influenza vaccine coverage reached 41.3%. The uptake of influenza vaccine was significantly higher among those receiving the reminder (9.3% vs. 7.1% in the control group, p < 0.001). Those who received a SMS reminder were 30% more likely to uptake seasonal influenza vaccine. By sex and age, the reception of the reminder was associated with a significantly higher probability of vaccination in men ≥65 years with at least a concurrent chronic condition (IRR: 1.58, CI95%: 1.25–2.00). Among women, this higher probability was detected in those between 14 and 64 years of age (IRR: 1.41, CI95%: 1.22–1.63), and ≥65 years without concurrent chronic conditions (IRR: 1.40, CI95%: 1.05–1.89). ConclusionAlthough the intervention was modestly effective, it proved beneficial in some cases. It can be an additional strategy to improve vaccine uptake, since it is simple, feasible, affordable and easily scalable, particularly when immunization and target population data are available in population registries.

Vaccination coverage in Qatar: Benchmarking with global figures.

Introduction: Vaccination is considered one of the most successful and cost-effective public health interventions of the 20th century. In 2017, Qatar's Expanded Program of Immunization (EPI) provided vaccination services against a comprehensive list of 15 vaccine-preventable diseases. Objectives: To assess the performance of Qatar's national immunization system, identify possible gaps by determining the national vaccination coverage rates, and benchmark these rates against regional and global figures. Methods: The data utilized herein were retrieved from the vaccination coverage estimates generated by the World Health Organization and United Nations International Children's Emergency Fund. Relevant local, regional, and global vaccination coverage figures were manually extracted and then analyzed for six vaccines (DTP3, Pol3, MCV2, HepB, PCV3, and RotaC) in 2017. Percentages and proportions were compared using the Chi-squared test. Results: Vaccination coverage levels in Qatar have surpassed the optimal level of 90% for all vaccines. Compared with international figures, the national coverage exceeds the relevant benchmarks. For DTP3 and Pol3, Qatar achieved 97% coverage compared with 99% coverage in Jordan and 85% coverage globally. For MCV2, Qatar achieved 93% coverage compared with 99% coverage in Jordan and 67% coverage globally. For RotaC, Qatar achieved 97% coverage compared with 96% coverage in Jordan and 28% coverage globally. For HepB, Qatar achieved 97% coverage compared with 43% coverage globally. Conclusions: Compared with the international benchmarks of major vaccines, the vaccination coverage rates in Qatar are high. However, challenges for maintaining high coverage, such as cultural and language barriers, should be addressed.

Assessing measles vaccine failure in Tianjin, China

Despite increasing global measles vaccination coverage, progress toward measles elimination has slowed in recent years. In China, children receive a measles-containing vaccine (MCV) at 8 months, 18–24 months, and some urban areas offer a third dose at age 4–6 years. However, substantial measles cases in Tianjin, China, occur among individuals who have received multiple MCV doses. This study describes the vaccination history of measles cases 8 months – 19 years old. Data came from measles cases in Tianjin’s reportable disease surveillance system (2009–2013), and from a case control study (2011–2015). Twenty-nine percent of those in the surveillance dataset and 54.4% of those in the case series received at least one dose of MCV. The minimum and median time-to-diagnosis since vaccination revealed an increase in time since vaccination for incremental doses. Considerable measles cases in Tianjin occur in vaccinated children, and further research is needed to understand the reasons for vaccine failure.

The Role of Mucosal Immunity in Pertussis.

Pertussis or whooping cough, mainly caused by Bordetella pertussis, is a severe respiratory disease that can affect all age groups but is most severe and can be life-threatening in young children. Vaccines against this disease are widely available since the 1950s. Despite high global vaccination coverage, the disease is not under control in any country, and its incidence is even increasing in several parts of the world. Epidemiological and experimental evidence has shown that the vaccines fail to prevent B. pertussis infection and transmission, although they are very effective in preventing disease. Given the high infection rate of B. pertussis, effective control of the disease likely requires prevention of infection and transmission in addition to protection against disease. With rare exceptions B. pertussis infections are restricted to the airways and do not usually disseminate beyond the respiratory epithelium. Therefore, protection at the level of the respiratory mucosa may be helpful for an improved control of pertussis. Yet, compared to systemic responses, mucosal immune responses have attracted relatively little attention in the context of pertussis vaccine development. In this review we summarize the available literature on the role of mucosal immunity in the prevention of B. pertussis infection. In contrast to vaccination, natural infection in humans and experimental infections in animals induce strong secretory IgA responses in the naso-pharynx and in the lungs. Several studies have shown that secretory IgA may be instrumental in the control of B. pertussis infection. Furthermore, studies in mouse models have revealed that B. pertussis infection, but not immunization with current acellular pertussis vaccines induces resident memory T cells, which may also contribute to protection against colonization by B. pertussis. As these resident memory T cells are long lived, vaccines that are able to induce them should provide long-lasting immunity. As of today, only one vaccine designed to induce potent mucosal immunity is in clinical development. This vaccine is a live attenuated B. pertussis strain delivered nasally in order to mimic the natural route of infection. Due to its ability to induce mucosal immunity it is expected that this approach will contribute to improved control of pertussis.

Global Routine Vaccination Coverage - 2017.

Endorsed by the World Health Assembly in 2012, the Global Vaccine Action Plan 2011-2020 (GVAP) (1) calls on all countries to reach ≥90% national coverage with all vaccines in the country's national immunization schedule by 2020. This report updates previous reports (2,3) and presents global, regional, and national vaccination coverage estimates and trends as of 2017. It also describes the number of infants surviving to age 1 year (surviving infants) who did not receive the third dose of diphtheria and tetanus toxoids and pertussis-containing vaccine (DTP3), a key indicator of immunization program performance (4,5), with a focus on the countries with the highest number of children who did not receive DTP3 in 2017. Based on the World Health Organization (WHO) and United Nations Children's Fund (UNICEF) estimates, global DTP3 coverage increased from 79% in 2007 to 84% in 2010, and has remained stable from 2010 to 2017 (84% to 85%). In 2017, among the 19.9 million children who did not receive DTP3 in the first year of life, 62% (12.4 million) lived in 10 countries. From 2007 to 2017, the number of children who had not received DTP3 decreased in five of these 10 countries and remained stable or increased in the other five. Similar to DTP3 coverage, global coverage with the first measles-containing vaccine dose (MCV1) increased from 80% in 2007 to 84% in 2010, and has remained stable from 2010 to 2017 (84% to 85%). Coverage with the third dose of polio vaccine (Pol3) has remained stable at 84%-85% since 2010. From 2007 to 2017, estimated global coverage with the second MCV dose (MCV2) increased from 33% to 67%, as did coverage with the completed series of rotavirus (2% to 28%), pneumococcal conjugate (PCV) (4% to 44%), rubella (26% to 52%), Haemophilus influenzae type b (Hib) (25% to 72%) and hepatitis B (HepB) (birth dose: 24% to 43%; 3-dose series: 63% to 84%) vaccines. Targeted, context-specific strategies are needed to reach and sustain high vaccination coverage, particularly in countries with the highest number of unvaccinated children.