National Immunization Schedule Research Articles

The impact of the COVID-19 pandemic on parents' behavior toward scheduled pediatric vaccinations in Saudi Arabia.

Coronavirus disease (COVID-19) is caused by a newly discovered coronavirus and has resulted in a global pandemic. The World Health Organization recommended avoiding any delay or disruption of immunization services, as this could result in increases in outbreak-prone vaccine-preventable diseases. This study aimed to determine the impact of the COVID-19 pandemic on parents' behaviour towards their children's scheduled vaccinations. This web-based cross-sectional study recruited 1,143 parents/guardians of children below six years of age living in Saudi Arabia between May 1 and May 30, 2020 via social media platforms. A self-developed online questionnaire consisting of eight items was used. Simple and multiple binary logistic regression was used to determine the factors associated with vaccine delay during the COVID-19 pandemic. The parents/guardians were aged 20-60 years; 82% were aged between 20 and 39 years. It was found that 26% of parents did not vaccinate their children on time according to the national immunization schedule in regular situations, and 38% of parents reported delaying vaccination due to the COVID-19 pandemic. The multiple logistic regression analysis found that having two or more children, living in Riyadh or the Western region or not vaccinating children during regular situations were associated with an increased risk of vaccine delay during the COVID-19 pandemic. Delaying children's vaccinations during the COVID-19 pandemic was influenced most by living in regions with high COVID-19 prevalence and having two or more children.

Immunization status of children in Nepal and associated factors, 2016

BackgroundNepal has made substantial improvements in childhood immunization uptake. However, vaccination levels are still below the country-specific Sustainable Development Goal target of 94.8% coverage by 2025 for children aged 12–23 months who received all immunizations recommended in the national immunization schedule by their first birthday. A better understanding of the predictors of full immunization can inform successful programmatic interventions to improve coverage while also guiding resource allocation to ensure all children are fully vaccinated. This study estimates childhood immunization coverage in Nepal and characterizes the association between immunization status and various sociodemographic predictors. MethodsData from the 2016 Nepal Demographic and Health Survey were used to examine the immunization status of children aged 12–23 months. Immunization status was categorized as fully immunized (receiving all recommended doses), under-immunized (receiving at least one, but not all, recommended doses), and un-immunized (not receiving any doses of any vaccine). Associations between full and under-immunization and potential sociodemographic predictors were assessed using logistic regression. ResultsAmong 976 children, 78.2% were fully immunized, 21% were under-immunized, and 0.8% were un-immunized. Retention of an immunization card was significantly associated with full immunization status. Mothers who had completed a formal education above secondary school and mothers who were working at time of interview had increased odds of full immunization. Birthing in an institutional setting was also associated with higher odds of full immunization. ConclusionsOverall, immunization coverage in Nepal is relatively high, although it varies by dose and sociodemographic factors. Almost 25% of Nepalese children were not fully immunized, leaving them at increased risk for vaccine-preventable disease related morbidity and mortality. Nepal must continue focused efforts to reach every child and minimize the equity gap; programs may focus on advocating for the use of immunization cards, education and empowerment for girls, and delivery in institutional settings.

Public trust, information sources and vaccine willingness related to the COVID-19 pandemic in Trinidad and Tobago: an online cross-sectional survey

BackgroundThe response of populations to public health measures may rely on the degree to which the population trusts sources of information and institutions. There has been little research in this area in the Caribbean. This exploratory study aimed to evaluate public trust in information sources, confidence in institutions and COVID-19 vaccine willingness in Trinidad and Tobago.MethodsAn exploratory online survey was conducted in Trinidad and Tobago from November 10th to December 7th 2020. The survey instrument was a validated questionnaire developed by the World Health Organisation (WHO) and adapted to the local setting. Descriptive statistics and regression analyses were used to analyse the data.FindingsThe most trusted sources of information included health workers (32.5%) and the ministry of health (23.6 %). Increasing levels of trust in the medical sector were associated with decreasing levels of believing misinformation. Overall, 62.8 % of participants said they would take the COVID-19 vaccine if available. Regression analyses showed those who agreed that everyone should adhere to the national immunization schedule and those who would take the flu vaccine, were 2.77 (95% CI 1.77-4.35) and 4.60 (95% CI 3.11-6.84) timesmore likely to take the vaccine, respectively.InterpretationOur study found increasing trust in health sources, confidence in medical sector, adherence to the national immunisation schedule and acceptance of the flu vaccine may increase COVID-19 vaccine willingness rates. Although the generalisability of the findings is limited, the results of this exploratory survey may be used to identify areas for prioritisation and improvement in future research.

To study the immunization status of children aged 1-5 years admitted to department of pediatrics, Lala Lajpat Rai & Associated Hospitals, GSVM Medical College, Kanpur

The Present study was conducted in the Department of Pediatrics of Lala Lajpat Rai & Associated Hospital GSVM Medical College, Kanpur. All the children aged between 1-5 years, admitted in Department of Pediatrics were asked to participate in this study. Information regarding vaccination, socio-demographic factors was collected from their parents and care takers. Accuracy and validity of information were confirmed by immunization card in possible situation and inspection for BCG scar. Hospital based descriptive cross-sectional study.In upper class, 100% of children were completely immunized. In upper middle class, 80.8% children had complete and 19.1% partial immunization status. No one remained unimmunized in upper middle class. In lower middle class, 33.9% of children were completely immunized, 59.6% partially immunized and 6.4% remained unimmunized.Children who were 1stin birth order, had maximum immunization coverage (44.8%). Minimum immunization coverage was in birth order >4 (3.2%). P value is <0.001, indicates the significant relation between birth order and immunization status. As birth order increased, immunization coverage decreased. In this present hospital based descriptive cross –sectional study, we found that 51.2% children were fully immunized, 45.6% were partially immunized and 3.2% children were unimmunized as per National immunization schedule. Children belonging to upper class were 100% completely immunized. In upper middle class 80.8% children in lower middle class 33.9%, in upper lower class 55.7% and in lower class 50.9% children were completely immunized respectively. In lower class immunization coverage was higher than lower middle class. Droprate for BCG to pentavalent 1 was 10.64%, similarly dropout from BCG to measles was 12.7%. Dropout rate of pentavalent 1 to pentavalent 2 was 1.4%, pentavalent2 to pentavalent3 was 2.6%. It indicates that system is not able to hold the child once registered. Steps for improvement should focus on reducing the drop rate from BCG to pentavalent and measles.

Hepatitis B vaccination coverage in Germany: systematic review

BackgroundDespite being considered as a low prevalence country for hepatitis B (HBV), some populations in Germany are at higher risk of infection. In the context of the World Health Organization’s (WHO) viral hepatitis elimination goals, a valid epidemiological data base is needed to plan and monitor the national response. Prevention strategies include general and targeted HBV vaccination programmes.ObjectiveThe aim of this work was to estimate the HBV vaccination coverage (VC) in the general population (GP) and different population groups in Germany from available evidence and to identify current evidence gaps for future research.MethodsWe conducted a systematic review on HBV VC in the general population and populations at high risk of HBV exposure or severe infection in Germany. We included eligible publications (01/01/2017 to 06/06/2020) from databases Embase, Pubmed and Livivo, from a previous scoping review (including data published 01/01/2005–17/03/2017), from the national surveillance system and screened the reference lists of all publications at full text level. Risk of bias was assessed using the Hoy et al. tool.ResultsWe included 68 publications of 67 studies and assigned them to one or more suitable population groups. Twenty-one studies contained data among children/adolescents and three among adults from the GP (VC 65.8–90.5% and 22.9–52.1%, respectively), one among travelers (VC 89.0%), 13 among immunocompromised populations (VC 7.8–89.0%), 16 among populations with occupational risk and 16 with non-occupational risk of HBV exposure (VC 63.6–96.5% and 4.4–84.5%, respectively).ConclusionComprehensive evidence at low risk of bias was identified for children/adolescents. However, 25 years after including HBV in the national immunisation schedule, VC in Germany is still below the 95%-goal defined by WHO. For people at occupational risk of HBV exposure, VC was mostly reported to be over the WHO goal of 80%, but quality of evidence was heterogenous and should be improved. For people at non-occupational risk of HBV exposure, evidence was sparse and of low quality. The low VC highlights the need for future research to plan vaccination programmes targeting these populations.

Preventive vaccination compliance among medical students and pediatricians during the COVID-19 pandemic

The novel coronavirus disease (COVID-19) pandemic has become a strength test for the national healthcare systems and medical professional communities. The pandemic gave a revealing insight into the provision of resuscitation care, a shortage of personnel and protective equipment, and the lack of effective drugs to treat a novel, poorly studied infection. Objective. To identify the attitude towards immunoprophylaxis in general and against the coronavirus infection (COVID-19) in particular among medical students and pediatricians and to assess the dynamics of compliance to vaccination in these groups. Materials and methods. The survey was conducted among the 5-6-year students of the medical and pediatric faculties of the Ryazan State Medical University (RSMU) of the Ministry of Health of Russia in 2017 and 2021, the groups of students included 250 and 225 people, respectively. The children’s polyclinic pediatrician groups included 45 and 60 people in 2017 and 2021, respectively. The survey was conducted anonymously, face-to-face, and without compulsion. The identical questionnaires asked students 13 questions and pediatricians 10 questions with suggested response options. Results and discussion. The percentage of students who correctly named the number of vaccine preventable diseases in the National Immunisation Schedule has significantly decreased; the number of students who were not aware of the availability of the chickenpox vaccine has increased by 1.9 times. In 2021, the number of students giving priority to domestic vaccines decreased by 2.3 times, and the number of those choosing imported drugs as better and safer ones has increased by 1.5 times. In 2021, the number of senior students who were vaccinated against influenza doubled as compared to 2017. At the same time, the students agreed to recommend their patients to be vaccinated against influenza 1.4 times more often. During the 2021 pediatrician survey, the number of respondents, who preferred imported vaccines as better and safer ones, increased by 4 times, and the number of domestic vaccine advocates decreased by 1.8 times. In addition, the number of pediatricians who did not decide on this issue has increased by 9.8 times. Сonclusion. The results of the survey showed that there is still a lack of compliance to vaccine prophylaxis in certain groups of the professional medical community. The student cohort showed a decrease in knowledge and confidence in the vaccine prophylaxis. Among practitioners, there has been a positive trend towards an increase in the percentage of pediatricians, who considered it expedient to vaccinate children with chronic pathology.

Burden of rotavirus disease in young children in Iceland – Time to vaccinate?

BackgroundAcute gastroenteritis poses a significant burden on young children, families, health care facilities and societies. Rotavirus is the most common pathogen, but rotavirus infections are vaccine preventable. Information on the epidemiology of gastroenteritis in Icelandic children has until now not been available and rotavirus vaccination is currently not offered to Icelandic infants. The objective of this study was to assess the burden of rotavirus acute gastroenteritis in young children in Iceland and determine the potential benefit of adding rotavirus vaccine to the Icelandic childhood immunization schedule. MethodsFor a two-year period, children < 6 years old attending a children’s emergency department for acute gastroenteritis were recruited at the Children’s Hospital in Reykjavík, Iceland. Demographic information and Vesikari scores were registered. Stool samples were analyzed for pathogens. Duration of symptoms, treatment given, and secondary household infections were among the collected information. Annual cost of the infections in young children was estimated based on health care expenditures and lost days of parental work. Results325 children were included in the study, 75% of which were ≤ 24 months old. A pathogen was identified in 80% of cases, of which rotavirus was identified in 54%. Rotavirus caused a more severe disease than other pathogens, more often leading to fluid treatment in the emergency department and admissions. Median duration of rotavirus-illness was six days and caused a median of four days lost from work by parents. The estimated annual cost of rotavirus acute gastroenteritis was €2.9 million. ConclusionsRotavirus causes significant disease burden in young children. Although rarely life-threatening in high income countries, the costs for society are substantial. The inclusion of rotavirus vaccine in the national immunization schedule will reduce the disease burden and would be cost-saving in Iceland.

Trial design and protocol of randomized controlled trial comparing the efficacy of oral mefenamic acid, paracetamol and placebo for analgesic prophylaxis in childhood vaccination (MAP VaC trial)

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; Needle related pain has been one of the most important concerns for parents of children receiving vaccination. Non-steroidal anti-inflammatory drugs (NSAIDs) like paracetamol and mefenamic acid have been commonly used as analgesics in pediatric population. However, prophylactic administration of these drugs for analgesia during vaccination has not been studied. The main objective of this study is to compare the efficacy of prophylactic paracetamol, mefenamic acid and placebo on needle pain associated with vaccination.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; This is a three-arm parallel, triple blind, randomized controlled trial. Children aged 6 weeks to 7 years who need immunization as per national immunization schedule and reporting to pediatric outpatient department (OPD) at tertiary level hospital, AIIMS Mangalagiri, Andhra Pradesh, will be included. All participants will be randomly allotted to any of the three groups by computer based block randomization. Each participant will be given any one of the three drugs as per their allocation. Vaccination will be done as per national immunization schedule after 30 minutes of drug administration. Face, legs, activity, cry, consolability (FLACC) scoring will be done immediately after vaccine administration and repeated at 15 minutes and 30 minutes. All personnel involved in randomization, drug and vaccine administration, FLACC scoring and statistical analysis will be blinded along with parents and children enrolled in the study.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;If this intervention study shows evidence of a difference between drug and placebo signifying reduction in vaccine related pain with these drugs, this will have a huge impact on National Immunization programme by improving compliance, vaccine coverage and by reducing vaccine hesitancy.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Trial registration:&lt;/strong&gt; Clinical trials registration number is CTRI/2021/01/030239.&lt;/p&gt;

Assessment of Vaccine Herd Protection: Lessons Learned From Cholera and Typhoid Vaccine Trials.

Vaccine herd protection is the extension of the defense conferred by immunization beyond the vaccinated to unvaccinated persons in a population, as well as the enhancement of the protection among the vaccinated, due to vaccination of the surrounding population. Vaccine herd protection has traditionally been inferred from observations of disease trends after inclusion of a vaccine in national immunization schedules. Rather than awaiting outcomes of widescale vaccine deployment, earlier-stage evaluation of vaccine herd protection during trials or mass vaccination projects could help inform policy decisions about potential vaccine introduction. We describe the components, influencing factors, and implications of vaccine herd protection and discuss various methods for assessing herd protection, using examples from cholera and typhoid vaccine studies.

The Impact of Haemophilus Influenzae and Streptococcus Pneumoniae Vaccination in Bacterial Meningitis in a Pediatric Referral Hospital in Mexico

Abstract Objective This study aimed to compare the epidemiology of bacterial meningitis (BM) before and after vaccination, and identify possible risk factors associated with mortality. Methods The medical and microbiologic records of children (1 month–18 years) with a discharge diagnosis of BM in a third level children's hospital in Mexico from 1990 to 2018 were reviewed. The epidemiology, pathogens, and outcomes were compared before and after introducing Haemophilus influenzae type b (Hib) and pneumococcal conjugate vaccines to the Mexican immunization schedule. Risk factors associated with mortality were determined. Results In the 28-year period, 226 cases with BM were included 55.8% (1990–1999), 27.4% (2000–2008), and 16.8% (2009–2018) (p = 0.0001). The most frequent pathogen was Hib, documented in 39% of cases. There was a reduction in neurological complications after introducing the Hib conjugate vaccine (59 vs. 39%; p = 0.003) and sequelae after the Streptococcus pneumoniae conjugate vaccine (43 vs. 35%; p = 0.05). Independent risk factors associated with mortality were coma (odds ratio [OR]: 15 [2.9–78]), intracerebral bleeding (OR: 3.5 [1.4–12]), and pneumococcal meningitis (OR: 9.4 [2.2–39]). Conclusion Since the introduction of Hib and pneumococcal conjugate vaccines to the national immunization schedule, there was a reduction in BM cases, mainly associated with the Hib vaccine, with the consequent reduction of neurological complications and sequelae.

Immunization and Immunization Coverage According to National Immunization Schedule for Children Population: Cross-Sectional Multi-Centre Study

Background. Monitoring of documented vaccination is one of the indicators of the epidemiological supervision quality of preventive vaccination. It is crucial for epidemical situation prevention. Objective. The aim of the study is to estimate immunization and immunization coverage levels according to National Immunization Schedule (NIS) for children population in Russia. Methods. Immunization rates were estimated according to preventive vaccination cards (form №063/y) and children development cards (form №112/y) among children aged from 6 months to 15 years in 8 towns of Russia. Immunization was determined by the ratio of people who has fully performed all the vaccines from NIS (version of the year 2014), while immunization coverage – by the ratio people who has received at least one dose of corresponding vaccine. Results. The study has included data from 2,687 vaccinated children. The highest levels of immunization and immunization coverage were against tuberculosis (98.1% each), hepatitis B (85.9% and 96.5%), measles, mumps and rubella (84.4% and 93.9%). Immunization against diphtheria, pertussis and tetanus significantly differed from their immunization coverage (60.5% and 94.9%), as well as for poliomyelitis (65.0% and 94.9%). Relatively low immunization and immunization coverage levels were observed for pneumococcal infection (27.6% and 47.1%) and influenza (5.8% and 30.5%). The increase in the immunization level with age was observed for all vaccines, except pneumococcal vaccine. Conclusion. Immunization and immunization coverage against infections included in NIS vary significantly. The highest immunization and immunization coverage levels for all age groups were revealed for tuberculosis vaccine, and the lowest — for influenza vaccine.

Mothers' preferences and willingness-to-pay for human papillomavirus vaccines in Iran: A discrete choice experiment study.

This study aimed to identify mothers' preferences and willingness-to-pay (WTP) for human papillomavirus (HPV) vaccines (in this case, bivalent and quadrivalent) in Iran. We used a discrete choice experiment (DCE) method to present mothers with choices between two hypothetical profiles of vaccines, described by combinations of five attributes, each with two or three levels. We analyzed the DCE results using conditional logistic regression and measured WTP estimates for each attribute. Our response rate was 53.96%, while the completion rate for questioner was 93.57%. We identified protection against cervical cancer, protection against genital warts, protection duration, serious side effects, and cost to influence mothers' preferences for HPV vaccination. The relative importance for serious side effects was the highest among all attributes. Mothers' WTP for bivalent and quadrivalent HPV vaccines was in US $ -432 (US $1=IRR 42,000) and US $ 380, respectively. Quadrivalent vaccination could be the most suitable candidate for implementing the national immunization schedule. The reason is that mothers express more WTP for the quadrivalent vaccine than bivalent due to its protection against genital warts.

Evidence of Circulation of Several HAV Genetic Variants and Emergence of Potential Antigenic Variants in an Endemo-Epidemic Country before Vaccine Introduction.

Similar to several other countries in the world, the epidemiology of hepatitis A virus changed from high to intermediate endemicity level in Tunisia, which led to the occurrence of outbreaks. This study aimed to determine the genetic and antigenic variability of HAV strains circulating in Tunisia during the last few years. Genotyping using complete VP1 gene and VP1-2A junction confirmed the predominance of genotype IA, with co-circulation of several genetic and antigenic variants. Phylogenetic analysis including Tunisian and strains from other regions of the world showed the presence of at least two IA-variants within IA subgenotype. Amino-acid analysis showed several mutations in or close to epitope regions in the VP1-region. This study provides a baseline on the genetic and antigenic variability of HAV circulating strains before the introduction of vaccination into the national immunization schedule.

Impact of the SARS-CoV-2 pandemic on the administration of vaccines as per the national immunization schedule in children younger than 2 years.

The reduction in the number of visits to health care centers since the onset of the SARS-CoV-2 pandemic may affect mandatory vaccination. To assess the impact of the SARS-CoV-2 pandemic on the administration of the pentavalent and the measles, mumps, and rubella (MMR) vaccines to children younger than 2 years at the vaccination center of a children's hospital in the Autonomous City of Buenos Aires. Cross-sectional study using the vaccination center's digital records from January to May 2019 and 2020. Results. In the second fortnight of March 2020, vaccinations dropped by 64.2 %. When examining the first dose of the pentavalent and MMR vaccines, such reduction was 74.9 % and 55.1 %, respectively. As of the second fortnight of March 2020, vaccinations dropped by 64.2 % compared to the same period of the previous year.

Vaccine interchangeability: problems and prospects

Vaccines by different manufacturers are available for most of the vaccine-preventable infections covered by the National Immunisation Schedule of the Russian Federation. Determination of the possibility of replacing a vaccine in the case of routine or emergency vaccination still remains a challenging issue. The aim of the study was to substantiate the problem of vaccine interchangeability, outline specific challenges and ways of solving them, analyse criteria underlying evaluation of vaccine interchangeability in Russia, and international experience in this area. The procedure for determining the interchangeability of biological products, including vaccines, was established in the Decree of the Government of the Russian Federation of 5 September 2020, No. 1360 “On the procedure for determination of interchangeability of medicinal products for human use”. The paper analyses the applicability of the official criteria for interchangeability of biological products, including vaccines. It outlines the main problems of performing evaluation of vaccine interchangeability in accordance with the established criteria. It is concluded that the vaccine interchangeability criteria need to be clarified in order to allow for assessment of comparability of active substances, and comparison of efficacy, safety, and immunogenicity of vaccines, taking into account vaccination schedules for different age groups. The possibility of evaluating interchangeability based on the results of post-authorisation studies also needs clarification. It is also necessary to align patient information leaflets for interchangeable vaccines.

Prevalence and genetic diversity of gastroenteritis viruses in hospitalized children < 5 years of age in Maharashtra state, Western India, 2017-2019.

Four gastroenteritis viruses were responsible for 54% of the acute gastroenteritis (AGE) cases in children hospitalized between May 2017 and December 2019 in Pune city of Maharashtra state, Western India. The majority (79%) of the children were <2 years of age. The prevalence of Rotavirus A (RVA) was 30.5% followed by 14.3% for norovirus, 8.4% for adenovirus, and 5.5% for astrovirus. The severity of the disease was highest in patients with coinfections compared with the patients with a single infection or negative for all (p = 0.024). Genotyping analysis showed that the majority of the RVA-positive samples (66%) could be typed as G3P[8], 63.6% of the norovirus as GII.4 Sydney [P16], 44% of the adenovirus as type 41%, and 56.2% of the astrovirus as astrovirus type 1. The almost equivalent prevalence of rotavirus and nonrotaviruses and acute gastroenteritis (AGE) cases without known etiology in around 46% of the cases was noted in the present study. Our data highlight that after the recent inclusion of rotavirus vaccines as a part of the National Immunization schedule in India, conducting extensive AGE surveillance in children should include nonrotaviruses such as norovirus.

Well-being of children affected by HIV/AIDS in Bangladesh: a cross-sectional study

ABSTRACT Children affected by HIV or AIDS (CABA) are vulnerable to social consequences such as neglect, stigma, and exclusion, leading to poor child well-being. We assessed the well-being of CABA and the factors associated with it. Our sample included 288 CABA, aged 10–18 years, from four divisions of Bangladesh – Dhaka, Chittagong, Sylhet, and Khulna. The mean age of the children was 12.93 (±2.36) years. Among the children, 58% were boys, 78% were from rural areas, and 48.6% were receiving some form of HIV-sensitive social protection services from different non-governmental organizations. Around 91% of the children were continuing their education, 93% were vaccinated according to the national immunization schedule, and 13% were infected with HIV. We found that child well-being was not significantly associated with HIV-sensitive social protection services (OR: 0.88, 95% CI: 0.40–1.95), but with family wealth (OR: 5.23, 95% CI: 1.88–14.51). Therefore, we argue for HIV-sensitive social protection services that consider the economic well-being of the families of the CABA along with other well-being aspects.

Immunogenicity and safety of 7-valent pneumococcal conjugate vaccine (PCV7) in children aged 2–5 years in China

BackgroundThe widespread use of pneumococcal conjugate vaccines (PCVs) has significantly decreased pneumococcal disease worldwide. However, China has not adopted PCVs in their national immunization schedules and had only approved these vaccines for children aged 2–15 months by 2020. MethodsIn an open-label trial, enrolled healthy children aged 2–5 years old were randomized 1:1 and divided into a 7-valent pneumococcal conjugate vaccine (PCV7) group and a Haemophilus influenzae type b conjugate vaccine (Hib) group. Children in the PCV7 group received a single dose of PCV7, and the Hib group received a single dose of Hib vaccine. Blood samples were collected before and 6 months after vaccination. Immunogenicity and safety of PCV7 were assessed at prespecified time points. ResultsSix months after a single dose of PCV7, children in the PCV7 group for all 7 serotypes, IgG mean concentrations (GMCs) and opsonophagocytic geometric mean titres (GMTs) were significantly higher (P < .001) than at baseline, and the proportion of IgG ≥ 0.35 µg/mL ranged from 90.0% to 100%. Although the antibody level increased with age, preexisting antibodies did not induce hyporesponsiveness to PCV7. In the Hib group, the antibody levels were not significantly different or had changed slightly at 6 months. PCV7 was well tolerated in all age groups, and no serious adverse events (AEs) emerged during this study. ConclusionsA single dose of PCV7 was immunogenic and safe for Chinese children aged 2–5 years, and the preexisting antibodies against the PCV7 serotypes did not change the response to vaccination. The findingssupported the effectiveness of PCV7 in this age group. PCVs with broader serotype coverage are expected to expand pneumococcal disease protection.

Evaluation of varicella vaccine effectiveness during outbreaks in schools or nurseries by cross-sectional study

ObjectiveThe aim of this study was to elucidate vaccine effectiveness (VE) during varicella outbreaks in schools and nurseries in Japan. MethodsAn outbreak was defined as emergence of three or more cases of varicella within 21 days at the same institute. Clinical information such as varicella vaccination status, and history of varicella was collected. If a child had varicella during the outbreak, information about absences, fever, and disease severity was collected. ResultsFrom September 2018 to January 2020, four outbreaks were reported around our institute from three elementary schools and one nursery. A total of 676 children were analyzed in this study. Seventy-six children (11.2%) were unvaccinated, 309 (45.7%) had received one dose of vaccine, and 291 (43.0%) had received two doses. Most children in Pre-K2 (1–2 years old) to Pre-K6 (5–6 years old), who were the targets of the national immunization schedule, received two doses. Meanwhile, most children older than third grade received single dose. Seventy-five children (11.1%) had varicella. Varicella prevalence from Pre-K5 to the third grade was greater than 10%. The adjusted VEs of single- and two-dose of varicella vaccine were 57.8% and 89.0%. The number of days absent was significantly longer in unvaccinated children than single-dose recipients (P = 0.0145). Unvaccinated children had significantly more severe skin eruptions than single-dose recipients (P = 0.0046) and two-dose recipients (P = 0.0258). ConclusionsAlthough VEs of single-dose varicella vaccination during outbreaks was not high, the VE of two-dose vaccination was similar to that in a previously reported case-control study.

#22: Trends in Bacterial Meningitis in a Tertiary-Level Children′s Hospital in Mexico, Following Haemophilus influenzae and Streptococcus pneumoniae Vaccination (1990–2018)

Abstract Background Bacterial meningitis (BM) remains a significant global health problem in pediatric care, with substantial morbidity and mortality. The epidemiology of BM has changed over the last 20 years. The ongoing introduction of conjugate vaccines for the most common meningeal pathogens has reduced the global incidence. However, there is limited epidemiologic and microbiologic data of BM in children before and after the widespread use of these vaccines in Mexico. Methods We conducted a retrospective, observational, analytical study. Pediatric patients (from 1 month to 18 years of age) presenting with BM and hospitalized at the Instituto Nacional de Pediatria in Mexico City, from 1990 to 2018, were included. Meningitis from invasive procedures or complicated head trauma were excluded. BM was classified according to the World Health Organization (WHO) criteria. The cases were analyzed in three periods: period A (1990–1999), period B (2000–2008), and period C (2009–2018). Period A corresponds to the time before the conjugate Haemophilus influenzae type b (Hib vaccine) was introduced in Mexico, while periods B and C correspond to the time after the Hib vaccine was routinely applied. Periods A and B correspond to the period before the pneumococcal conjugate vaccine (PCV7) was administrated in Mexico, while period C is after PCV7 and PCV13 were routinely administrated. The proportion of cases between periods was compared with Chi-square or Fisher exact test; P &amp;lt; 0.05 was considered significant. Binomial logistic regression analysis was used to determine the association between potential risk factors and death due to BM. Results A total of 226 cases with BM were included, 180 (79.6%) confirmed cases, and 46 (20.4%) probable cases. The median age at diagnosis was 10 months. There were 126 (55.8%) cases in Period A, 62 (27.4%) cases in Period B, and 38 (16.8%) cases in Period C, with a statistically significant reduction between periods (P = 0.0001). Hib was the most commonly isolated pathogen, found in 38 (50%) cases. However, its proportion declined significantly after the introduction of the Hib conjugate vaccine (P &amp;lt; 0.0001). S. pneumoniae followed as the second most commonly isolated bacterial pathogen. There was a significant reduction in neurological complications after the Hib conjugate vaccine (P = 0.003) and the S. pneumoniae conjugate vaccine (P = 0. 05) were introduced. Independent risk factors associated with mortality were coma (OR 15, P = 0. 0001), intracerebral bleeding (OR 3.5, P = 0.046), and pneumococcal meningitis (OR 9.4, P = 0. 002). Conclusions BM remains a cause of morbidity and mortality in pediatric patients in this hospital, with a dramatic change in the epidemiology since the introduction of the Hib conjugate vaccine to the national immunization schedule. Routine use of childhood conjugate vaccines against the most frequent etiological agents reduced the number of cases globally, mainly those caused by Hib. Additionally, conjugate vaccines reduced neurological complications and sequelae caused by this disease.