Impact of haemophilus influenzae type b conjugate vaccine in South Africa and Argentina

Outbreak of Meningitis in Iraq in 2023

Objective. To determine clinical presentations and laboratory findings of meningitis outbreak among children in 2023 in Iraq. Method. the demographic data (gender, age, symptoms, and disease transmission among family members) were collected from child patients, who were admitted to Halabja and Sulaimania pediatric teaching hospital in the period of 15 March 2023 to 1st of August, 2023. The blood and cerebrospinal fluid (CSF) specimens were collected for hematological, biochemical, microscopic, and microbiological examinations, including culturing and FilmArray meningitis/encephalitis panel. Results. The population studied were 170 children between 1 and 18 years old, Males were 110 (64.7%), and females were 60 (35.3%). Children between 5 and 10 years old had the highest frequency, whereas only 2 children were <1 year. Clinical symptoms were fever in 100%, followed by headache, vomiting, convulsion, photophobia, and lethargy (79%, 12%, 3%, 3%, 2%) respectively. CSF parameters were: 38.8% of them had >1000 leucocytes/µ, followed by 31.2% for those who had <300 cells/µ, differential CSF leucocytes, 82.4% were monocytes, and sugar was normal at 84.1%. while protein was <40 mg/d in 55.9% of them. Conclusion. Meningitis outbreak due to enterovirus was recorded, and age predilection and clinical presentation refer to different serotypes. Further work is needed to define the species and serotypes of the virus and define the environmental source of the virus.

Conjugate vaccines dramatically reshaped the epidemiology of bacterial meningitis in a well-defined child population

AIM

We explored the impact of vaccination on bacterial meningitis in a well-defined population of children on the island of Crete, Greece, over a 27-y period.

METHODS

This was a retrospective observational study of all mandatory notifications of bacterial meningitis in patients aged 1 mo-14 y from 1991 to 2017.

RESULTS

There were 245 patients with proven (n = 227) or suspected (n = 18) bacterial meningitis, and eight deaths were recorded, giving a case fatality rate of 3.3%. The mean annual incidence rate (IR) per 100 000 children was 4.9 for Neisseria meningitidis, 2.2 for Streptococcus pneumoniae and 0.4 for Haemophilus influenzae type b (Hib). Cases of meningitis C dropped significantly after the conjugate meningitis C vaccine was licensed for routine vaccination in Greece in 2000 (IR of 1.5 vs 0.3, P < 0.028) while the Streptococcus pneumoniae cases showed a threefold decrease after the PCV13 vaccine was licensed in Greece in 2009 (IR 2.7 vs 1.0, P < 0.03). Vaccination had already eliminated Hib in Greece in the 1990s.

CONCLUSION

Bacterial meningitis cases decreased in children following the introduction of the meningitis C and PCV13 vaccines in Greece. Hib had already disappeared and significant reductions in meningitis C and Streptococcus pneumoniae were observed.

Acute bacterial meningitis in Iran: Systematic review and meta-analysis

Introduction

Bacterial meningitis persists in being a substantial cause of high mortality and severe neurological morbidity, despite the advances in antimicrobial therapy. Accurate data has not been available regarding the epidemiology of bacterial meningitis particularly in developing countries, yet. Indeed, the present systematic review provides a comprehensive data analysis on the prevalence and epidemiology of bacterial meningitis in Iran.

Methods

We systematically reviewed articles from 1994 to 2015. The reports which contained the prevalence and etiology of acute bacterial meningitis by valid clinical and laboratory diagnosis were comprised in the present study.

Results

Our analysis indicated that Streptococcus pneumoniae (30% [I2 = 56% p < 0.01]), Haemophilus influenza type b (15% [I2 = 82.75% p < 0.001]), coagulase negative staphylococci (CoNS) (14% [I2 = 60.5% p < 0.06]), and Neisseria meningitidis (13% [I2 = 74.16% p < 0.001]) were the most common cause of acute bacterial meningitis among meningitis cases in Iran. Notably, high frequency rates of nosocomial meningitis pathogens were detected in the present analysis.

Conclusions

It was magnificently attained that the majority of cases for bacterial meningitis in Iran could be avertable by public immunization schemes and by preventive care to inhibit the broadening of hospital acquired pathogens.

The effect of Haemophilus influenzae type B and pneumococcal conjugate vaccines on childhood meningitis mortality: a systematic review

Background

Two of the most prevalent causes of severe bacterial meningitis in children, Haemophilus influenzae type B (Hib) and Streptococcus pneumoniae, are preventable by existing vaccines increasingly available in developing countries. Our objective was to estimate the dose-specific effect of Hib and pneumococcal conjugate vaccines (PCV) on childhood meningitis mortality in low-income countries for use in the Lives Saved Tool (LiST).

Methods

We systematically searched and reviewed published vaccine efficacy trials and observational studies reporting the effect of Hib or PCV vaccines on organism-specific meningitis, bacterial meningitis and all-cause meningitis incidence and mortality among children less than five years old in low- and middle-income countries. Data collection and quality assessments were performed using standardized guidelines. For outcomes available across multiple studies (≥2) and approximating meningitis mortality, we pooled estimates reporting dose-specific effects using random effects meta-analytic methods, then combined these with meningitis etiology data to determine the preventable fraction of childhood meningitis mortality for inclusion in LiST.

Results

We identified 18 studies of Hib conjugate vaccines reporting relevant meningitis morbidity and mortality outcomes (2 randomized controlled trials [RCTs], 16 observational studies) but few provided dose-specific effects. A meta-analysis of four case-control studies examined the dose-specific effect of Hib conjugate vaccines on Hib meningitis morbidity (1 dose: RR=0.64, 95% CI 0.38-1.06; 2 doses: RR=0.09, 95% CI 0.03-0.27; 3 doses: RR=0.06, 95% CI 0.02-0.22), consistent with results from single RCTs. Pooled estimates of two RCTs provided evidence for the effect of three doses of PCV on vaccine-serotype meningitis morbidity (RR=0.16, 95% CI 0.02-1.20). We considered these outcomes of severe disease as proxy estimates for meningitis mortality and combined the estimates of protective effects with meningitis etiology data to provide an estimate of the preventable fraction of childhood meningitis mortality with three doses of Hib (38-43%) and pneumococcal conjugate vaccines (28-35%) for use in LiST.

Conclusions

Few RCTs or vaccine effectiveness studies evaluated the dose-specific impact of Hib and PCV vaccines on childhood meningitis mortality, necessitating use of proxy measures to estimate population impact in LiST. Our analysis indicates that approximately three-quarters of meningitis deaths are preventable with existing Hib and PCV vaccines.

Aetiological agents of cerebrospinal meningitis: a retrospective study from a teaching hospital in Ghana

BACKGROUND

Meningitis is an important cause of morbidity and mortality in low-resource settings. In sub-Saharan Africa, the meningitis belt has been characterized by particularly high and seasonal incidences of bacterial meningitis extending throughout life. Despite the progress being made in treating the condition, the mortality rates continue to be high, ranging between 2% and 30% globally. In Ghana, the mortality rate of meningitis has been estimated to range from 36% to 50%. However little information is available on the pathogens contributing to meningitis and their antimicrobial susceptibilities. Updated information is essential to adjust the recommendations for empirical treatment or prevention of meningitis which could have immense implications for local and global health.

METHODS

We retrospectively reviewed laboratory records of all patients suspected of bacterial meningitis who underwent a lumbar puncture from January 1, 2008 to December 31, 2010. Data were retrieved from laboratory record books and double entered into a Microsoft(®) excel spreadsheet.

RESULTS

Records of 4,955 cerebrospinal fluid samples were analysed. Of these, 163 (3.3%, 95%CI: 2.8% to 3.8%) were confirmed meningitis and 106 (2.1%, 95%CI: 1.7% to 2.6%) were probable meningitis cases. Confirmed meningitis cases were made up of 117 (71.8%) culture positive bacteria, 19 (11.7%) culture positive Cryptococcus neoformans and 27(16.6%) Gram positive bacteria with negative culture. The most prevalent bacteria was Streptococcus pneumoniae 91 (77.7%), followed by E.coli 4 (3.4%), Salmonella species 4 (3.4%), Neisseria meningitidis 3 (2.5%), Pseudomonas species 3(2.5%) and others. Pneumococcal isolates susceptibility to penicillin, chloramphenicol and ceftriaxone were 98.9% (95%CI: 94.0% to 100.0%), 83.0% (95%CI: 73.4% to 90.1%) and 100.0% (95%CI: 95.8% to 100.0%) respectively.

CONCLUSION

Streptococcus pneumoniae is an important cause of meningitis among all age groups and its susceptibility to penicillin and ceftriaxone still remains very high. Ghanaians of all ages and possibly other developing countries in the meningitis belt could benefit from the use of the pneumococcal vaccine. Other bacterial and fungal pathogens should also be considered in the management of patients presenting with meningitis.

Haemophilus influenzae type b conjugate vaccines - a South African perspective

Introduction of Hib vaccine is known to positively impact on reduction of both morbidity and mortality in children less than 5 years of age. Incorporation of this vaccine into a National EPI, however, does come at a significant cost, which is especially important in non-GAVI funded countries. Compounded reduction in response in certain patient populations and possible indication of booster doses further impacts on cost-benefit analyses. Despite these issues, South Africa has supplied Hib vaccine as part of the National EPI in the form of a combination vaccine, Pentaxim, which combines Hib with Diphtheria, Tetanus, acellular Pertussis (DTP) and Poliomyelitis since 2009. Prior to this, another combination vaccine was utilized containing Hib and DTP. This has subsequently lead to a significant reduction in invasive Hib disease post-introduction, therefore largely justifying utilization.

Economic burden of acute lower respiratory tract infection in South African children

BACKGROUND

Acute lower respiratory tract infections (ALRTI) are a leading cause of childhood mortality, but there are few data on disease costs in developing countries.

OBJECTIVES

This study's purpose was to analyse ALRTI's costs-of-illness and economic burden in urban South African children.

METHODS

ALRTI costs-of-illness (expressed in US$ 2010) at a tertiary hospital were measured using a micro-costing approach nested within a clinical trial. Demographic, epidemiological and data on use of health resources were integrated with costs-of-illness to estimate the economic burden of ALRTI in urban South African children aged <5 years.

RESULTS

745 children experiencing 858 ALRTI episodes were studied. 338 (39.4%), 513 (59.8%) and 7 (0.8%) episodes were managed in short-stay, paediatric ward and intensive care settings, respectively. Mean lengths of stay in short-stay, paediatric ward and intensive care (ICU) were 1.4, 8.1 and 14.4 days, respectively. The societal costs-of-illness per ALRTI episode managed in short-stay and paediatric ward settings, respectively, were US$266 (95% CI 245-286) and 1287 (95% CI 1174-1401) in HIV-infected patients, and US$257 (95% CI 247-267) and 1032 (95% CI 931-1133) in HIV-uninfected patients. Family costs were not collected in ICUs. ICU direct medical costs were US$5968 (95% CI 4025-8056) in HIV-uninfected patients and US$7849 in one HIV-infected patient. Under-5 children experienced an estimated 424,220 episodes annually of ALRTI. ALRTI treatment cost the public health system an estimated US$28,975,000 while an additional US$539,000 of costs were borne by families.

CONCLUSION

ALRTIs in children <5 years impose a heavy economic burden on families and the South African public health-care system.

Acute bacterial meningitis in infants and children: epidemiology and management

Acute bacterial meningitis (ABM) continues to be associated with high mortality and morbidity, despite advances in antimicrobial therapy. The causative organism varies with age, immune function, immunization status, and geographic region, and empiric therapy for meningitis is based on these factors. Haemophilus influenzae type b (Hib), Streptococcus pneumoniae, and Neisseria meningitidis cause the majority of cases of ABM. Disease epidemiology is changing rapidly due to immunization practices and changing bacterial resistance patterns. Hib was the leading cause of meningitis in children prior to the introduction of an effective vaccination. In those countries where Hib vaccine is a part of the routine infant immunization schedule, Hib has now been virtually eradicated as a cause of childhood meningitis. Vaccines have also been introduced for pneumococcal and meningococcal diseases, which have significantly changed the disease profile. Where routine pneumococcal immunization has been introduced there has been a reported increase in invasive pneumococcal disease due to non-vaccine serotypes. In those parts of the world that have introduced conjugate meningococcal vaccines, there has been a significant change in the epidemiology of meningococcal meningitis. As a part of the United Nations Millennium Development Goal 4, the WHO has introduced a new vaccine policy to improve vaccine availability in resource poor countries. In addition, antibiotic resistance is an increasing problem, especially with pneumococcal infection. Effective treatment focuses on early recognition and use of effective antibiotics. This review will attempt to focus on the changing epidemiology of ABM in pediatric patients due to vaccination, the changing patterns of infecting bacterial serotypes due to vaccination, and on antibiotic resistance and its impact on current management strategies.

Pneumonia in severely malnourished children in developing countries - mortality risk, aetiology and validity of WHO clinical signs: a systematic review

OBJECTIVES

To quantify the degree by which moderate and severe degrees of malnutrition increase the mortality risk in pneumonia, to identify potential differences in the aetiology of pneumonia between children with and without severe malnutrition, and to evaluate the validity of WHO-recommended clinical signs (age-specific fast breathing and chest wall indrawing) for the diagnosis of pneumonia in severely malnourished children.

METHODS

Systematic search of the existing literature using a variety of databases (Medline, EMBASE, the Web of Science, Scopus and CINAHL).

RESULTS

Mortality risk: Sixteen relevant studies were identified, which universally showed that children with pneumonia and moderate or severe malnutrition are at higher risk of death. For severe malnutrition, reported relative risks ranged from 2.9 to 121.2; odds ratios ranged from 2.5 to 15.1. For moderate malnutrition, relative risks ranged from 1.2 to 36.5. Aetiology: Eleven studies evaluated the aetiology of pneumonia in severely malnourished children. Commonly isolated bacterial pathogens were Klebsiella pneumoniae, Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, and Haemophilus influenzae. The spectrum and frequency of organisms differed from those reported in children without severe malnutrition. There are very few data on the role of respiratory viruses and tuberculosis. Clinical signs: Four studies investigating the validity of clinical signs showed that WHO-recommended clinical signs were less sensitive as predictors of radiographic pneumonia in severely malnourished children.

CONCLUSIONS

Pneumonia and malnutrition are two of the biggest killers in childhood. Guidelines for the care of children with pneumonia and malnutrition need to take into account this strong and often lethal association if they are to contribute to the UN Millennium Development Goal 4, aiming for substantial reductions in childhood mortality. Additional data regarding the optimal diagnostic approach to and management of pneumonia and malnutrition are required from regions where death from these two diseases is common.

Bacterial meningitis following introduction of Hib conjugate vaccine in northern Uganda

BACKGROUND

St Mary's Hospital, Lacor is in Gulu district in northern Uganda. Owing to conflict and insurgency, the majority of the hospital population live in internally displaced people's camps. There is ongoing public health surveillance of paediatric bacterial meningitis by the hospital. Before the introduction of Haemophilus influenza type b (Hib) conjugate vaccine in June 2002, Hib was the leading cause of bacterial meningitis in the area.

METHODS

All patients with suspected bacterial meningitis between April 2003 and August 2006 were recruited. Meningitis was confirmed by isolation of bacteria.

RESULTS

During the study period, 4986 cases of suspected bacterial meningitis were identified, 395 of whom had purulent cerebrospinal fluid (CSF). A culture was obtained from 259 (65%): Streptococcus pneumoniae 132 (51%), H. influenzae 22 (8.5%), salmonella spp 85 (32.8%), Neisseria meningitidis 9 (3.5%) and others 11 (4.2%). Over the surveillance period, there was a remarkable decline in the prevalence of H. influenza meningitis to only three cases or fewer per year compared with 42 in 2001. The minimum incidence of Streptococcus pneumoniae meningitis among children under 5 years of age was 33.7/100,000 of population and it was more prevalent during the dry season. The minimum incidence of non-typhoidal salmonella spp meningitis was 22.7/100,000, making it the second most common cause of paediatric bacterial meningitis with a case fatality rate of 18.2%.

CONCLUSION

Hib conjugate vaccine delivered through the national immunisation programme is very effective in reducing Hib meningitis in children under 5 years of age. Continued laboratory-based surveillance of bacterial meningitis in Africa is needed to assess the effectiveness of vaccination programmes and detect other vaccine-preventable pathogens.

The impact of vaccines on pneumonia: key lessons from Haemophilus influenzae type b conjugate vaccines

This article explores key lessons learned from vaccination with Haemophilus influenzae type b (Hib) conjugate vaccine and how these lessons may provide insight into the impact of emergent pneumococcal vaccines against pneumonia. The worldwide value of Hib vaccination for reducing Hib disease burden and carriage is reviewed. Using comparisons of data for pneumococcus versus Hib, the article concludes that epidemiological and biological differences between these pathogens will complicate efforts to use results from the Hib vaccine experience to predict outcomes following pneumococcal conjugate vaccine introduction.

Haemophilus influenzae type b antibodies in vaccinated and non-vaccinated children

BACKGROUND

Invasive Haemophilus influenzae type b (Hib) infection has a high morbidity among young children, but the burden of disease and rate of Hib are different in different regions. The aim of the present study was to investigate the levels of Hib antibodies and the oropharyngeal Hib prevalence in young children.

METHODS

One hundred-fifty nine healthy children aged 19-36 months of age were included in this cross-sectional study. Anti-polyribosylribitol phosphate (anti-PRP) antibody concentrations were measured using commercially available enzyme-linked immunosorbent assay (ELISA), and serotyping of isolated Hib strains was conducted by slide agglutination with specific antisera.

RESULTS

Of the study participants, 57 (35.8%) were fully vaccinated (group 1A); 17 (10.7%) were incompletely vaccinated (group 1B), and 85 (53.5%) were non-vaccinated (group 2). Geometric mean titer (GMT) of anti-PRP antibody was 3.8 microg/mL, 2.2 microg/mL and 0.49 microg/mL in group 1A, group 1B and group 2, respectively. While all children in group 1 (n = 74) had seroprotective antibody concentrations (>/=0.15 microg /mL), of the children in group 2 (n = 85) 31.8% did not have seroprotective anti-PRP levels (P < 0.0001). A total of 68.2% in group 2 had natural immunity. Nineteen children (33.3%) in group 1, and 46 (54.1%) in group 2 had oropharyngeal Hib colonization (P = 0.0004).

CONCLUSIONS

Hib conjugate vaccine is immunogenic and reduces Hib colonization. Each country should investigate the burden of Hib disease and the natural immunity in young children, and should determine antigenic dose, number of doses administered and dose intervals before deciding whether to introduce Hib conjugate vaccine in routine immunization programs.

Haemophilus influenzae type b conjugate vaccine use and effectiveness

Haemophilus influenzae type b (Hib) is an important cause of invasive bacterial disease in children, including meningitis and pneumonia. The introduction of Hib conjugate vaccines into routine vaccination schedules has contributed to a substantial reduction in the burden of Hib-related disease in many developed countries. However, introduction of Hib conjugate vaccines in developing countries has progressed more slowly. We review the worldwide use and effectiveness of Hib conjugate vaccines. At present, 119 countries have programmes for routine Hib immunisation. WHO estimates that in the developed world 92% of the eligible population is vaccinated against Hib; however, average coverage is 42% in developing countries and only 8% in the poorest countries. Africa and southeast Asia have the lowest rates of Hib vaccine introduction. Vaccine costs and debate about the burden of disease are obstacles to the global use of Hib conjugate vaccine. Even with new funding support, there are many ongoing challenges and vaccine use remains suboptimal, particularly in developing countries.

Introduction of Hib vaccine into national immunization programmes: A descriptive analysis of global trends

Despite the demonstration of effectiveness and public health impact of Hib conjugate vaccines, the majority of infants from poorest countries do not yet have access to this safe and effective preventive intervention. This paper provides a descriptive analysis of the main characteristics of countries that have included Hib vaccine in their national immunization programmes before 2006. It highlights the importance of regularly analyzing the process of decision-making involved in implementation of public health interventions, in order to learn from cumulative experience and expedite the introduction of future interventions.

Effect of age, polymicrobial disease, and maternal HIV status on treatment response and cause of severe pneumonia in South African children: a prospective descriptive study

BACKGROUND

HIV-related pneumonia is the main cause of paediatric hospital admissions in southern Africa. We aimed to measure predictors of treatment failure and the cause of non-responsive pneumonia in children admitted to hospital with severe pneumonia in Durban, South Africa.

METHODS

We investigated 358 children aged 1-59 months who presented with WHO-defined severe or very severe pneumonia. Children were recruited irrespective of HIV status and started on a standard antimicrobial regimen of benzylpenicillin and gentamicin. All infants also received high-dose trimethoprim-sulfamethoxazole. The primary outcome measure was treatment failure at 48 h.

FINDINGS

242 (68%) children were HIV infected, 41 (12%) HIV exposed, uninfected, and 75 (21%) HIV uninfected. Failure to respond by 48 h was predicted by age under 1 year (adjusted odds ratio 6.38, 95% CI 2.72-14.91, p<0.0001), very severe disease (2.47, 1.17-5.24, p=0.0181), HIV status (HIV infected 10.3, 3.26-32.51; HIV exposed, uninfected 6.02, 1.55-23.38; p=0.0003), and polymicrobial disease (one organism 2.06, 1.05-4.05; two organisms 10.75, 4.38-26.36; p<0.0001) on logistic regression analysis. All children with three organisms failed treatment. 72/110 treatment failures had at least two organisms isolated. Three of nine HIV-exposed, uninfected infants, 29/74 HIV-infected, but no HIV-uninfected infants who failed study therapy had Pneumocystis jirovecii pneumonia.

INTERPRETATION

For children younger than 1 year, the WHO guidelines are inadequate and need to be revised since both HIV-infected and HIV-exposed, uninfected infants had more treatment failures than did HIV-uninfected infants. Polymicrobial disease is an important reason for treatment failure, and we need to identify rapid low-cost diagnostic methods to assist clinicians.

Introduction of Haemophilus influenzae type B conjugate vaccine into routine immunization in Ghana and its impact on bacterial meningitis in children younger than five years

This report shows the impact of a pentavalent vaccine that includes Haemophilus influenzae type b (Hib) conjugate vaccine on bacterial meningitis in children younger than 5 years in Ghana. A review of the first 3 years of a pediatric bacterial meningitis surveillance program, started in August 2001 in Accra, Ghana, was undertaken. There was a significant reduction, P = 0.042 and 0.017, in percentage of purulent meningitis in children younger than 1 year, comparing the first year when the vaccine was introduced, to the second and third years, respectively.

Laboratory-based surveillance of patients with bacterial meningitis in Egypt (1998–2004)

Laboratory-based surveillance for bacterial meningitis was conducted in a network of infectious disease hospitals in Egypt to better understand the epidemiology of this infection. Healthcare and laboratory personnel were trained in basic surveillance and microbiologic processing of cerebrospinal fluid (CSF) specimens. All bacterial isolates from CSF were confirmed and tested for antimicrobial susceptibility. PCR testing was performed on a random subset of purulent, culture-negative CSF specimens. Of 11,070 patients who met criteria for the case definition, 843 (8%) were culture positive (42% positive for Streptococcus pneumoniae, 20% for Haemophilus influenzae serotype b, 17% for each of Neisseria meningitidis and Mycobacterium tuberculosis, and 6% for other bacteria). Of 1,784 (46%) CSF specimens tested by PCR, 232 (13%) were positive for the first three major pathogens. Of N. meningitidis isolates, 52% belonged to serogroup A, 35% to serogroup B, and 4% to serogroup W135. S. pneumoniae isolates comprised 46 different serotypes, of which 6B, 1, 19A, 23F, and 6A were the most predominant. The overall case-fatality rate for culture-positive cases was 26% and was highest among patients with M. tuberculosis (47%). Factors significantly associated with death (p < 0.05) included admission to rural hospitals, long prodromal period, referral from other hospitals, antibiotic treatment prior to admission, and clear CSF (<100 cells/mm3). Susceptibility to ampicillin and ceftriaxone was observed in 44 and 100% of H. influenzae serotype b isolates and in 52 and 94% of S. pneumoniae isolates, respectively. This surveillance highlights the significant mortality and morbidity associated with bacterial meningitis in Egypt. Decision makers need to review current treatment guidelines and introduce appropriate vaccines for prevention and control of the disease.

The impact of routine infant immunization with Haemophilus influenzae type b conjugate vaccine in Malawi, a country with high human immunodeficiency virus prevalence

Malawi has extreme poverty and a high-human immunodeficiency virus (HIV) prevalence. Following Haemophilus influenzae type b (Hib) conjugate vaccine introduction during 2002, we evaluated vaccine impact by reviewing hospital surveillance data for acute bacterial meningitis in Blantyre district among children age 1-59 months admitted during 1997-2005. Documented annual Hib meningitis incidence rates decreased from 20-40/100,000 to near zero among both rural and urban residents despite no change in pneumococcal meningitis incidence rates. Before vaccine introduction, an average of 10 children/year had Hib meningitis and HIV infection compared to 2/year during 2003-2004 and none during 2005. Vaccine effectiveness was high following two or more doses of vaccine. The most urgent future need is for a sustainable routine infant immunization program, including a less expensive vaccine that preferably is delivered in a multivalent form.

Bacterial meningitis in children

Microbiologic causes of meningitis include bacteria, viruses, fungi, and parasites. Before routine use of pneumococcal conjugate vaccine, bacterial meningitis affected almost 6000 people every year in the United States, and about half of all cases occurred in children 18 years old or younger. Prompt and accurate diagnosis and adequate treatment of bacterial meningitis in children remains a major challenge, as reflected by the continued high morbidity and case-fatality rates of the disease worldwide. Appropriate use of antibiotics, along with adjunctive therapies, such dexamethasone, has proved helpful in the prevention of neurologic sequelae in children with bacterial meningitis. Better understanding of pathophysiologic mechanisms likely would result in more effective therapies in the future.