Sylvestre R. M. Tiendrebéogo

Bio: Sylvestre R. M. Tiendrebéogo is an academic researcher. The author has contributed to research in topics: Meningococcal disease & Vaccination. The author has an hindex of 10, co-authored 11 publications receiving 802 citations.

Impact of the Serogroup A Meningococcal Conjugate Vaccine, MenAfriVac, on Carriage and Herd Immunity

Abstract: Background The conjugate vaccine against serogroup A Neisseria meningitidis (NmA), MenAfriVac, was first introduced in mass vaccination campaigns of 1-29-year-olds in Burkina Faso in 2010. It is not known whether MenAfriVac has an impact on NmA carriage. Methods We conducted a repeated cross-sectional meningococcal carriage study in a representative portion of the 1-29-year-old population in 3 districts in Burkina Faso before and up to 13 months after vaccination. One district was vaccinated in September 2010, and the other 2 were vaccinated in December 2010. We analyzed 25 521 oropharyngeal samples, of which 22 093 were obtained after vaccination. Results In October-November 2010, NmA carriage prevalence in the unvaccinated districts was comparable to the baseline established in 2009, but absent in the vaccinated district. Serogroup X N. meningitidis (NmX) dominated in both vaccinated and unvaccinated districts. With 4 additional sampling campaigns performed throughout 2011 in the 3 districts, overall postvaccination meningococcal carriage prevalence was 6.95%, with NmX dominating but declining for each campaign (from 8.66% to 1.97%). Compared with a baseline NmA carriage prevalence of 0.39%, no NmA was identified after vaccination. Overall vaccination coverage in the population sampled was 89.7%, declining over time in 1-year-olds (from 87.1% to 26.5%), as unvaccinated infants reached 1 year of age. NmA carriage was eliminated in both the vaccinated and unvaccinated population from 3 weeks up to 13 months after mass vaccination (P = .003). Conclusions The disappearance of NmA carriage among both vaccinated and unvaccinated populations is consistent with a vaccine-induced herd immunity effect.

Bacterial Meningitis in Burkina Faso: Surveillance Using Field-Based Polymerase Chain Reaction Testing

Abstract: Background. In addition to frequent epidemics of group A meningococcal disease endemic bacterial meningitis due mostly to Neisseria meningitidis pneumococcus and Haemophilus influenzae type b is a serious problem in sub- Saharan Africa. The improved ability to identify the etiologic agent in cases of bacterial meningitis will facilitate more rapid administration of precise therapy. Methods. To describe the epidemiology of bacterial meningitis and evaluate the usefulness of field-based polymerase chain reaction (PCR) testing we implemented population-based meningitis surveillance in Burkina Faso during 2002-2003 by use of PCR culture and antigen detection tests. Results. Among persons aged 1 month to 67 years the incidences of menigococcal meningitis pneumococcal meningitis and Haemophilus influenzae type b meningitis were 19 cases (n = 179) 17 cases (n = 162) and 7.1 cases (n = 68) per 100000 persons pr year respectively. Of the cases of meningococcal meningitis 72% were due to N. meningitidis serogroup W135. Pneumoccocal meningitis caused 61% of deaths and occurred in a seasonal pattern that was similar to that of meningococcal meningitis. Of cases of pneumococcal meningitis and N. meningitidis serogroup W135 meningitis 71% occurred among persons >2 years of age. Most patients regardless of the etiology of their illness and the existence of an epidemic received short-course therapy with oily chloramphenicol. Compared with culture as the gold standard the sensitivity and specificity of PCR in the field were high; this result was confirmed in Burkina Faso and Paris. Conclusions. Precise and rapid identification of etiologic agents is critical for improvement in the treatment and prevention of meningitis and thus PCR should be considered for wider use in Africa. Vaccines against Streptococcus pneumoniae N. meningitidis (including serogroup W135) and H. influenzae type b all will have a major impact on the bacterial meningitis burden. Antibiotic recommendations need to consider the importance of S. pneumoniae even during the epidemic season. (authors)

Serogroup A meningococcal conjugate vaccination in Burkina Faso: analysis of national surveillance data

Abstract: Summary Background An affordable, highly immunogenic Neisseria meningitidis serogroup A meningococcal conjugate vaccine (PsA–TT) was licensed for use in sub-Saharan Africa in 2009. In 2010, Burkina Faso became the first country to implement a national prevention campaign, vaccinating 11·4 million people aged 1–29 years. We analysed national surveillance data around PsA–TT introduction to investigate the early effect of the vaccine on meningitis incidence and epidemics. Methods We examined national population-based meningitis surveillance data from Burkina Faso using two sources, one with cases and deaths aggregated at the district level from 1997 to 2011, and the other enhanced with results of cerebrospinal fluid examination and laboratory testing from 2007 to 2011. We compared mortality rates and incidence of suspected meningitis, probable meningococcal meningitis by age, and serogroup-specific meningococcal disease before and during the first year after PsA–TT implementation. We assessed the risk of meningitis disease and death between years. Findings During the 14 year period before PsA–TT introduction, Burkina Faso had 148 603 cases of suspected meningitis with 17 965 deaths, and 174 district-level epidemics. After vaccine introduction, there was a 71% decline in risk of meningitis (hazard ratio 0·29, 95% CI 0·28–0·30, p N meningitidis dropped significantly to 0·01 per 100 000 individuals per year, representing a 99·8% reduction in the risk of meningococcal A meningitis (CIR 0·002, 95% CI 0·0004–0·02, p Interpretation Early evidence suggests the conjugate vaccine has substantially reduced the rate of meningitis in people in the target age group, and in the general population because of high coverage and herd immunity. These data suggest that fully implementing the PsA–TT vaccine could end epidemic meningitis of serogroup A in sub-Saharan Africa. Funding None.

Epidemiology, Diagnosis, and Antimicrobial Treatment of Acute Bacterial Meningitis

Abstract: Summary: The epidemiology of bacterial meningitis has changed as a result of the widespread use of conjugate vaccines and preventive antimicrobial treatment of pregnant women. Given the significant morbidity and mortality associated with bacterial meningitis, accurate information is necessary regarding the important etiological agents and populations at risk to ascertain public health measures and ensure appropriate management. In this review, we describe the changing epidemiology of bacterial meningitis in the United States and throughout the world by reviewing the global changes in etiological agents followed by specific microorganism data on the impact of the development and widespread use of conjugate vaccines. We provide recommendations for empirical antimicrobial and adjunctive treatments for clinical subgroups and review available laboratory methods in making the etiological diagnosis of bacterial meningitis. Finally, we summarize risk factors, clinical features, and microbiological diagnostics for the specific bacteria causing this disease.

Laboratory medicine in Africa: a barrier to effective health care.

Abstract: Providing health care in sub-Saharan Africa is a complex problem. Recent reports call for more resources to assist in the prevention and treatment of infectious diseases that affect this population, but policy makers, clinicians, and the public frequently fail to understand that diagnosis is essential to the prevention and treatment of disease. Access to reliable diagnostic testing is severely limited in this region, and misdiagnosis commonly occurs. Understandably, allocation of resources to diagnostic laboratory testing has not been a priority for resource-limited health care systems, but unreliable and inaccurate laboratory diagnostic testing leads to unnecessary expenditures in a region already plagued by resource shortages, promotes the perception that laboratory testing is unhelpful, and compromises patient care. We explore the barriers to implementing consistent testing within this region and illustrate the need for a more comprehensive approach to the diagnosis of infectious diseases, with an emphasis on making laboratory testing a higher priority.