Pediatric disease burden and vaccination recommendations: understanding local differences

Individual and community-level determinants of pentavalent vaccination dropouts among under-five children in the sub-Saharan African countries: A multilevel analysis of the recent demographic and health survey

Background

Globally, each year, about 3 million deaths among children are prevented by pentavalent vaccinations. However, in developing countries, particularly in Sub-Saharan Africa, pentavalent vaccination dropout rates are not well reported. Therefore, this study aimed to assess pentavalent vaccination dropout rates and their determinants among under-five children in Sub-Saharan Africa.

Methods

Data from the recent Demographic and Health Surveys in 33 Sub-Saharan African countries were used for analysis. The study used a total of 358,529 under-five children. The determinants of pentavalent vaccination dropout were determined using a multilevel mixed-effects logistic regression model. Significant factors associated with pentavalent vaccination dropout were declared significant at p-values < 0.05. A model with the lowest deviance and highest logliklihood ratio was selected as the best-fit model.

Results

In Sub-Saharan Africa, one in five under-five children had pentavalent vaccination dropout rates. Factors such as Age (AOR = 1.61, 95 % CI: 1.51, 1.72), educational level (AOR = 1.30, 95 % CI: 1.22, 1.40), place of delivery (AOR = 1.65, 95 % CI: 1.57, 1.73), ANC visits (AOR = 1.34, 95 % CI: 1.23, 1.45), postnatal check-up (AOR = 1.19, 95 % CI: 1.14, 1.25), wealth status (AOR = 1.09, 95 % CI: 1.04, 1.15), distance to health facility (AOR = 1.08, 95 % CI: 1.03, 1.13), media exposure (AOR = 1.12, 95 % 1.15), and geographical region (AOR = 1.60, 95 % CI: 1.49, 1.72) had higher odds of pentavalent vaccination dropouts.

Conclusions

Pentavalent vaccination dropout rates in sub-Saharan Africa among under-five children were high. Both individual and community-level variables were determinants of pentavalent vaccination dropout rates. Government and ministry of health in Sub-Saharan Africa should give attention to those mothers of under-five children who reported distance as a big problem in accessing health facilities and to women who do not utilise antenatal and postnatal check-ups while designing policies and strategies in sub-Saharan Africa.

Incomplete immunization and associated factors among children 12-23 months in Aletawondo district, Sidama zone, South Ethiopia: Across-sectional study

Immunization is one of the most cost-effective and commonly used public health strategies for preventing child mortality. The goal of this study was to determine the prevalence of incomplete immunization and associated variables in children aged 12-23 months in the Aleta Wondo district of Southern Ethiopia. The researchers utilized a community-based cross-sectional study approach. A modified World Health Organization-Expanded Program on Immunization cluster sampling method was used to choose 634 mothers/caregivers of children aged 12-23 months. Data were collected by trained data collectors between March and April 2019. Descriptive statistics and logistic regression were done. In this study, 138 (21.8%) of children were not completed their immunization. Mothers who were literate [AOR = 2.1; (95% CI: 1.1, 4.2)]. Home birth [AOR = 2.9; (95% CI: 1.7, 5.3)], walking time from home to vaccination site [AOR = 1.95; (95% CI: 1.1,3.3)], inconvenience times for vaccination service [AOR = 2.4; (95% CI: 1.3,4.5)], postponing vaccination session schedule [AOR = 2.4; (95% CI:1.1,5.4)], households not visited by health extension workers [AOR = 4.1; (95% CI: 2.2,7.4)], poorer knowledge about child immunization [AOR = 4; (95% CI:2.2,7.5)] were factors associated with incomplete immunization. Incomplete immunization was higher compared to the national target. It is necessary to strengthen the program by enhancing the number of outreach sites considering the size of the target group.

Full vaccination coverage and associated factors among children aged 12 to 23 months in remote rural area of Demba Gofa District, Southern Ethiopia

Background

Full vaccination refers to the administration of vaccines/antigens recommended for children in the first year of life. However, little is known about full vaccination in remote, rural Ethiopia. This study aimed to measure full vaccination coverage and associated factors among children aged 12 to 23 months in Demba Gofa District, Southern Ethiopia.

Methods

A community-based cross-sectional study was conducted in April and May 2019 using a multistage sampling technique to select 677 mothers with children 12-23 months of age. Data was collected using a pre-tested structured questionnaire, and data were edited, coded, entered, and cleaned using Epi Info v3.1 and analyzed using SPSS v20. Bivariate and multivariable logistic regression was used to understand associations between dependent and independent variables.

Results

Three-hundred and nine children (47.0%) were fully vaccinated, 274 (41.7%) were partially vaccinated, and 74 (11.3%) were not vaccinated at all. Children were more likely to be vaccinated if decisions were made jointly with husbands (AOR = 1.88, 95% CI [1.06-3.34]), were made by mothers (AOR = 4.03, 95% CI [1.66-9.78]), followed postnatal care (AOR = 5.02, 95% CI [2.28-11.05]), if the child's age for completing vaccination was known (AOR = 2.54, 95% CI [1.04-6.23]), and if vaccinations did not make the child sick (AOR = 0.32, 95% CI [0.16-0.64]).

Conclusion

Full vaccination coverage was less than average in the study district and far below the governmental target (90%) necessary for sustained control of vaccine-preventable diseases. Interventions targeted towards maternal healthcare decision-making, postnatal care, knowledge on vaccination timing, and importance should be prioritized to improve full vaccination coverage. A continuous supply of vaccination cards needs to be ensured to improve vaccination conditions.

Spatial distribution of incomplete immunization among under-five children in Ethiopia: evidence from 2005, 2011, and 2016 Ethiopian Demographic and health survey data

BACKGROUND

An estimate of 2-3 million children under 5 die in the world annually due to vaccine-preventable disease. In Ethiopia, incomplete immunization accounts for nearly 16% of under-five mortality, and there is spatial variation for vaccination of children in Ethiopia. Spatial variation of vaccination can create hotspot of under vaccination and delay control and elimination of vaccine preventable disease. Thus, this study aims to assess the spatial distribution of incomplete immunization among children in Ethiopia from the three consecutive Ethiopia demographic and health survey data.

METHOD

A cross-sectional study was employed from Ethiopia demographic and health survey (2005, 2011and 2016) data. In total, 7901mothers who have children aged (12-35) months were included in this study. ArcGIS 10.5 Software was used for global and local statistics analysis and mapping. In addition, a Bernoulli model was used to analyze the purely spatial cluster detection of incomplete immunization. GWR version 4 Software was used to model spatial relationships.

RESULT

The proportion of incomplete immunization was 74.6% in 2005, 71.4% in 2011, and 55.1% in 2016. The spatial distribution of incomplete immunization was clustered in all the study periods (2005, 2011, and 2016) with global Moran's I of 0.3629, 1.0700, and 0.8796 respectively. Getis-Ord analysis pointed out high-risk regions for incomplete immunization: In 2005, hot spot (high risk) regions were detected in Kefa, Gamogofa, KembataTemibaro, and Hadya zones of SNNPR region, Jimma zone of Oromiya region. Similarly, Kefa, Gamogofa, Kembatatemibaro, Dawuro, and Hadya zones of SNNPR region; Jimma and West Arsi zones of Oromiya region were hot spot regions. In 2016, Afder, Gode, Korahe, Warder Zones of Somali region were hot spot regions. Geographically weighted regression identified different significant variables; being not educated and poor wealth index were the two common for incomplete immunization in different parts of the country in all the three surveys.

CONCLUSION

Incomplete immunization was reduced overtime across the study periods. The spatial distribution of incomplete immunization was clustered and High-risk areas were identified in all the study periods. Predictors of incomplete immunization were identified in the three consecutive surveys.

Immunogenicity and safety of a combined DTPa-IPV/Hib vaccine administered as a three-dose primary vaccination course and a booster dose in healthy children in Russia: a phase III, non-randomized, open-label study

We assessed the immunogenicity and safety of the combined diphtheria-tetanus-acellular pertussis-inactivated poliovirus/Haemophilus influenzae type b vaccine (DTPa-IPV/Hib) in children in Russian Federation aiming to support the registration of the vaccine in Russia. In this phase 3, non-randomized, open-label study (NCT02858440), healthy children received three primary doses at 3, 4.5, and 6 months of age (N = 235) and a booster dose at 18 months of age (N = 225). Seroprotection rates against diphtheria, tetanus, Hib, and poliovirus 1–3, seropositivity rates against pertussis antigens, and antibody geometric mean concentrations/titers for all antigens were evaluated one month post-primary and post-booster vaccinations. Solicited local and general adverse events (AEs) were collected during a 4-day period and unsolicited AEs during a 31-day period post-vaccination. Serious AEs were recorded throughout the study. At post-primary vaccination, all infants were seroprotected against diphtheria, tetanus, and poliovirus 1 and 2, 99.3% against poliovirus 3, and 98.4% against Hib. At least 98.9% of participants were seropositive for the three pertussis antigens. At post-booster vaccination, all toddlers were seroprotected/seropositive against all vaccine components. The most frequent local and general solicited AEs were redness, reported for 52.6% and 44.9% of children, and irritability, reported for 64.7% and 39.1% of children, post-primary and post-booster vaccination, respectively. Unsolicited AEs were reported for 20.4% (post-primary) and 5.8% of children (post-booster vaccination). Most AEs were mild or moderate in intensity. Six serious AEs were reported in three (0.4%) children; none were fatal or assessed as vaccination-related. DTPa-IPV/Hib proved immunogenic and well tolerated in the Russian pediatric population.

Socio-economic and demographic determinants of full immunization among children of 12-23 months in Afghanistan

Immunization is one of the most cost-effective interventions to reduce vaccine-preventable diseases morbidity and mortality. Vaccination coverage is very low in Afghanistan; National Risk and Vulnerability Assessment (NRVA) Survey 2008 estimated the coverage of fully immunized children to be 37%. The current study was designed to examine the factors influencing full immunization among children aged 12–23 months. Demographic and vaccination data of 2,561 children of 12–23 months was extracted from the Afghanistan Health Survey (AHS) 2012. The data was analyzed by logistic regression to estimate adjusted odds ratios (AOR) and 95% confidence intervals (CI). The study found that 38.8% of the children were fully immunized. The coverage for specific vaccines was 80.9% for BCG, 72.0% for OPV3, 64.8% for measles, and 50.1% for Penta3. Urban residence (AOR = 0.60, 95% CI 0.40–0.90 relative to rural), children of poorer families (AOR = 1.36, 95% CI 1.10–1.67 relative to poorest), some education (AOR = 1.59, 95% CI 1.20–2.11 relative to no education) and antenatal care (AOR = 1.70, 95% CI 1.44–2.01 relative to not received) were found to be significant predicators of full immunization. This study indicated that the full-immunization rate in Afghanistan was quite low compared to the national target of 90% coverage. Therefore, strategies taking into account the identified factors seem to be vital to improve vaccination coverage.

Immunogenicity and safety of a combined DTPa-IPV/Hib vaccine administered as a three-dose primary vaccination course in healthy Korean infants: phase III, randomized study

We assessed the immunogenicity and safety of a three-dose primary vaccination schedule with the combined diphtheria-tetanus-acellular pertussis-inactivated poliovirus/Haemophilus influenzae type b vaccine (DTPa-IPV/Hib) in Korean infants. In this phase III open-label, multicenter study (NCT01309646), healthy infants aged 42-69 days (randomized 1:1) received three doses of either pentavalent DTPa-IPV/Hib (DTPa-IPV/Hib group) or DTPa-IPV and Hib vaccines administered separately (DTPa-IPV+Hib group) at 2, 4, 6 months of age. The primary objective was to demonstrate non-inferiority of DTPa-IPV/Hib compared to DTPa-IPV+Hib vaccines in terms of immune responses to all vaccine antigens, 1 month post-dose 3. Solicited symptoms (local and general) were recorded during 4 days, and unsolicited adverse events (AEs) during 31 days, after each vaccination. Serious AEs (SAEs) were recorded throughout the study duration. The immunogenicity of the pentavalent DTPa-IPV/Hib vaccine was non-inferior compared to concomitant administration of DTPa-IPV+Hib vaccines. One month post-dose 3, nearly all infants had antibody levels above the seroprotective thresholds for anti-diphtheria toxoid, anti-tetanus toxoid, anti-polyribosyl-ribitol phosphate, and anti-poliovirus type 1, 2 and 3, and had antibody levels above the seropositive thresholds for anti-pertussis toxoid (PT), anti-filamentous hemagglutinin (FHA) and anti-pertactin (PRN) antibodies. A vaccine response for PT, FHA and PRN was observed in at least 96.7% of study participants. Anti-PRP geometric mean concentrations appeared lower for the DTPa-IPV/Hib group (8.456 µg/mL) than for the DTPa-IPV+Hib group (18.700 µg/mL). In both groups, the most common solicited symptoms were injection site redness and irritability. Fifty-seven SAEs were reported throughout the study; none were considered to be vaccination related.

Socio-demographic determinants of childhood immunization incompletion in Koforidua, Ghana

OBJECTIVE

Immunization saves more than 3 million lives worldwide each year, and it saves millions from suffering illness and lifelong disability. The study sought to assess the socio-demographic factors that influence childhood immunization incompletion. A cross-sectional descriptive design was employed for the study conducted at the Child Welfare Clinic in the Regional Hospital, Koforidua. A total of 280 caregivers/mothers who have children aged between 0 and 59 months were included in this study. Data were entered and analyzed using SPSS.

RESULTS

The study found that being divorced (p = 0.048) and working part-time (p = 0.049) has a significant and positive association with immunization incompletion. Women who were divorced [AOR (95% CI) 3.01 (1.59-58.2)] were 3 times less likely to complete immunization than those who were cohabiting, married and widowed taken into account the effect due to all the additional confounder variables included in the analysis. Women who were working part-time were 2.28 times less likely to complete immunization schedule than those working full-time; [AOR (95% CI) 2.28 (1.031-9.11)]. This study has documented socio-demographic factors influencing childhood immunization incompletion in the Regional Hospital, Koforidua. The Ministry of Health should, therefore, put in measures like public education to encourage mothers to complete each immunization schedule.

Assessment of Child Immunization Coverage and Associated Factors with Full Vaccination among Children Aged 12-23 Months at Mizan Aman Town, Bench Maji Zone, Southwest Ethiopia

Immunization remains one of the most important and cost-effective public health interventions to reduce child mortality and morbidity. Globally, it is estimated to avert between 2 and 3 million deaths each year. In Ethiopia, immunization coverage rates stagnated and remained very low for many years. Thus, this study was aimed to assess child immunization coverage and factors associated with full vaccination among children aged 12-23 months in Mizan Aman town. The study design was community-based cross-sectional survey. Data was collected by using pretested structured questionnaire. A total of 322 mothers/caretakers were interviewed. Based on vaccination card and mothers/caretakers' recall, 295 (91.6%) of the children took at least a single dose of vaccine. From total children, 27 (8.4%) were not immunized at all, 159 (49.4%) were partially immunized, and 136 (42.2%) were fully immunized. Mothers/caretakers educational level, fathers' educational level, place of delivery, maternal health care utilization, and mothers/caretakers knowledge about vaccine and vaccine-preventable disease showed significant association with full child immunization. The finding from this study revealed that child immunization coverage in the studied area was low. Thus the town health office and concerned stakeholders need to work more to improve performance of the expanded program on immunization in this area.

Profile and outcomes of critically ill children in a lower middle-income country

OBJECTIVE

To determine the clinical profile and outcome of critically ill children presenting to a paediatric ED in a lower middle-income country.

METHODS

We performed a retrospective analysis of children (<14 years) presenting to the ED of the National Institute of Child Health, Karachi, between January and December 2014 who were assigned to acuity 1 (requiring immediate life-saving interventions) according to the Emergency Severity Index. Data included demographic variables, presenting complaints, interventions and outcomes in the ED.

RESULTS

There were 172 162 visits during the year. Of these, 13 551 (8%) were level 1. 64% of level 1 patients were transported to the ED without ambulance service. Neonates (0-28 days) constituted 48% of level 1 children; their most frequent presenting complaints were respiratory symptoms, followed by fever and reluctance to feed. Above the neonatal age group, the most common presenting complaints were gastrointestinal symptoms (with signs of hypoperfusion), followed by seizures, reluctance to feed and respiratory symptoms. 64% of children of >28 days presenting were malnourished. Interventions included cardiopulmonary resuscitation, application of bubble continuous positive airway pressure and endotracheal intubation. Overall mortality was 13%; 63% of all deaths were in the neonatal age group.

CONCLUSION

Children with the highest triage acuity represent 8% of all visits to a paediatric ED. In this group, neonates account for nearly half of all the children, and more than half of all the deaths among critically ill children came in ED. A large proportion of high-acuity children are malnourished.

Safety, immunogenicity and persistence of immune response to the combined diphtheria, tetanus, acellular pertussis, poliovirus and Haemophilus influenzae type b conjugate vaccine (DTPa-IPV/Hib) administered in Chinese infants

We conducted 3 phase III, randomized, open-label, clinical trials assessing the safety, reactogenicity (all studies), immunogenicity (Primary vaccination study) and persistence of immune responses (Booster study) to the combined diphtheria, tetanus, pertussis, poliomyelitis, and Haemophilus influenzae type b vaccine (DTPa-IPV/Hib) in Chinese infants and toddlers.

In the Pilot study (NCT00964028), 50 infants (randomized 1:1) received 3 doses of DTPa-IPV/Hib at 2–3–4 (Group A) or 3–4–5 months of age (Group B). In the Primary study (NCT01086423), 984 healthy infants (randomized 1:1:1) received 3 doses of DTPa-IPV/Hib at 2–3–4 (Group A) or 3–4–5 (Group B) months of age, or concomitant DTPa/Hib and poliomyelitis (IPV) vaccination at 2–3–4 months of age (Control group); 825 infants received a booster dose of DTPa/Hib and IPV at 18–24 months of age (Booster study; NCT01449812).

In the Pilot study, unsolicited symptoms were more frequent in Group A (16 versus 1 infant; mostly upper respiratory tract infection and pyrexia); this observation was attributed to an epidemic outbreak of viral infections. Non-inferiority of 3-dose primary vaccination with DTPa-IPV/Hib over separately administered DTPa/Hib and IPV was demonstrated for Group A (primary objective). Similar antibody concentrations were observed in all groups, except for anti-polyribosyl-ribitol phosphate and anti-poliovirus types 1–3 which were higher in DTPa-IPV/Hib recipients. Protective antibody levels against all vaccine antigens remained high until booster vaccination. Three-dose vaccination with DTPa-IPV/Hib had a clinically acceptable safety profile.

Old Disease and New Challenges: Major Obstacles of Current Strategies in the Prevention of Pertussis

Context

Universal immunization against Bordetella pertussis has partially controlled the burden of the disease and its transmission. However, according to recent data, the epidemiology of this vaccine-preventable disease has changed. Now, younger infants, adolescents, and adults are at greater risk of infection. This article has studied the interaction between the various factors involved in the changing epidemiology of pertussis and the major obstacles faced by the current strategies in its prevention.

Evidence Acquisition

In this narrative review, the most recently published sources of information on pertussis control measures, consisting of textbooks and articles, have been reviewed. We focused on the more recent data about the changing epidemiology or pertussis in Scopus through the use of the MeSH-term words [pertussis] or [whooping cough] and [epidemiology] or [outbreak] or [resurgence], but our search was not restricted to this particular strategy; we also tried to find all of the most recent available data in the general field through other means.

Results

Primary and booster doses of the pertussis vaccine seem to partially control transmission of the disease, but despite the different preventive strategies available, pertussis continues to cause mortality and morbidity among high-risk groups.

Conclusions

Adding booster doses of acellular pertussis vaccine to the current national immunization practices with whole-cell vaccines for young adults and pregnant women seems to be a good option for controlling mortality and morbidity among high-risk groups such as very young infants.

The pediatric disease spectrum in emergency departments across Pakistan: data from a pilot surveillance system

BACKGROUND

There is an increasing number of urgently ill and injured children being seen in emergency departments (ED) of developing countries. The pediatric disease burden in EDs across Pakistan is generally unknown. Our main objective was to determine the spectrum of disease and injury among children seen in EDs in Pakistan through a nationwide ED-based surveillance system.

METHODS

Through the Pakistan National Emergency Department Surveillance (Pak-NEDS), data were collected from November 2010 to March 2011 in seven major tertiary care centers representing all provinces of Pakistan. These included five public and two private hospitals, with a collective annual census of over one million ED encounters.

RESULTS

Of 25,052 children registered in Pak-NEDS (10% of all patients seen): 61% were male, 13% under 5 years, while almost 65% were between 10 to < 16 years. The majority (90%) were seen in public hospital EDs. About half the patients were discharged from the EDs, 9% admitted to hospitals and only 1.3% died in the EDs. Injury (39%) was the most common presenting complaint, followed by fever/malaise (19%) and gastrointestinal symptoms (18%). Injury was more likely in males vs. females (43% vs. 33%; p < 0.001), with a peak presentation in the 5-12 year age group (45%).

CONCLUSIONS

Pediatric patients constitute a smaller proportion among general ED users in Pakistan. Injury is the most common presenting complaint for children seen in the ED. These data will help in resource allocation for cost effective pediatric ED service delivery systems. Prospective longer duration surveillance is needed in more representative pediatric EDs across Pakistan.

Pertussis Across the Globe: Recent Epidemiologic Trends From 2000 to 2013

Pertussis has reemerged as a problem across the world. To better understand the nature of the resurgence, we reviewed recent epidemiologic data and we report disease trends from across the world. Published epidemiologic data from January 2000 to July 2013 were obtained via PubMed searches and open-access websites. Data on vaccine coverage and reported pertussis cases from 2000 through 2012 from the 6 World Health Organization regions were also reviewed. Findings are confounded not only by the lack of systematic and comparable observations in many areas of the world but also by the cyclic nature of pertussis with peaks occurring every 3-5 years. It appears that pertussis incidence has increased in school-age children in North America and western Europe, where acellular pertussis vaccines are used, but an increase has also occurred in some countries that use whole-cell vaccines. Worldwide, pertussis remains a serious health concern, especially for infants, who bear the greatest disease burden. Factors that may contribute to the resurgence include lack of booster immunizations, low vaccine coverage, improved diagnostic methods, and genetic changes in the organism. To better understand the epidemiology of pertussis and optimize disease control, it is important to improve surveillance worldwide, irrespective of pertussis vaccine types and schedules used in each country.

B-cell responses after intranasal vaccination with the novel attenuated Bordetella pertussis vaccine strain BPZE1 in a randomized phase I clinical trial

Despite high vaccination coverage, pertussis is still a global concern in infant morbidity and mortality, and improved pertussis vaccines are needed. A live attenuated Bordetella pertussis strain, named BPZE1, was designed as an intranasal vaccine candidate and has recently been tested in man in a phase I clinical trial. Here, we report the evaluation of the B-cell responses after vaccination with BPZE1. Forty-eight healthy males with no previous pertussis-vaccination were randomized into one of three dose-escalating groups or into a placebo group. Plasma blast- and memory B-cell responses were evaluated by ELISpot against three different pertussis antigens: pertussis toxin, filamentous haemagglutinin and pertactin. Seven out of the 36 subjects who had received the vaccine were colonized by BPZE1, and significant increases in the memory B-cell response were detected against all three tested antigens in the culture-positive subjects between days 0 and 28 post-vaccination. The culture-positive subjects also mounted a significant increase in the filamentous haemagglutinin-specific plasma blast response between days 7 and 14 post-vaccination. No response could be detected in the culture-negatives or in the placebo group post-vaccination. These data show that BPZE1 is immunogenic in humans and is therefore a promising candidate for a novel pertussis vaccine. This trial is registered at ClinicalTrials.gov (NCT01188512).

Are healthcare workers' intentions to vaccinate related to their knowledge, beliefs and attitudes? A systematic review

BACKGROUND

The Summit of Independent European Vaccination Experts (SIEVE) recommended in 2007 that efforts be made to improve healthcare workers' knowledge and beliefs about vaccines, and their attitudes towards them, to increase vaccination coverage. The aim of the study was to compile and analyze the areas of disagreement in the existing evidence about the relationship between healthcare workers' knowledge, beliefs and attitudes about vaccines and their intentions to vaccinate the populations they serve.

METHODS

We conducted a systematic search in four electronic databases for studies published in any of seven different languages between February 1998 and June 2009. We included studies conducted in developed countries that used statistical methods to relate or associate the variables included in our research question. Two independent reviewers verified that the studies met the inclusion criteria, assessed the quality of the studies and extracted their relevant characteristics. The data were descriptively analyzed.

RESULTS

Of the 2354 references identified in the initial search, 15 studies met the inclusion criteria. The diversity in the study designs and in the methods used to measure the variables made it impossible to integrate the results, and each study had to be assessed individually. All the studies found an association in the direction postulated by the SIEVE experts: among healthcare workers, higher awareness, beliefs that are more aligned with scientific evidence and more favorable attitudes toward vaccination were associated with greater intentions to vaccinate. All the studies included were cross-sectional; thus, no causal relationship between the variables was established.

CONCLUSION

The results suggest that interventions aimed at improving healthcare workers' knowledge, beliefs and attitudes about vaccines should be encouraged, and their impact on vaccination coverage should be assessed.