Dataset Information

Seroprevalence of pertussis in Senegal: a prospective study.

ABSTRACT:

Background

Pertussis, also known as whooping cough, is a vaccine-preventable respiratory disease caused by Bordetella pertussis infection, against which Senegalese children are immunized with the diphtheria-tetanus-whole cell pertussis vaccine (DTwP). Seroepidemiology of pertussis has been widely described in industrialized countries, but rare are the studies referring to it in developing countries.

Methods

We conducted a longitudinal survey in Northern Senegal to investigate the epidemiology of B. pertussis by evaluating the IgG antibody (Ab) response against pertussis toxin (PT). A cohort of 410 children aged 1 to 9 from five villages in the Middle Senegal River Valley were followed-up for 18 months. During that period, five visits were made to assess the immunological status of the children.

Principal findings

PT-specific IgG responses were significantly different according to age. Until the age of 3, there was a decrease in the Ab response, which then increased in the older groups. Assessment of IgG antibodies to PT (IgG-PT) suggested evidence of recent exposures to the pathogen. Surprisingly, in one of the five villages the average Ab response to PT was very low at all ages during the first 6 months of the study. At the third visit, IgG-PT concentrations peaked to very high levels, to slightly decline at the end of the survey. This indicates an outbreak of B. pertussis, whereas in the other villages a pertussis endemic profile could be observed.

Conclusions

Pertussis is endemic in Northern Senegal despite the introduction of vaccination. The circulation of the bacteria seems to differ between geographic locations and over time. A more complete understanding of the epidemiology of pertussis and its environmental determinants could provide information to adapt vaccination programs.

SUBMITTER: Gaayeb L

PROVIDER: S-EPMC3485356 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Publications

Seroprevalence of pertussis in Senegal: a prospective study.

Gaayeb Lobna L Sarr Jean Biram JB Ndiath Mamadou O MO Hanon Jean-Baptiste JB Hanon Jean-Baptiste JB Debrie Anne-Sophie AS Seck Modou M Schacht Anne-Marie AM Remoué Franck F Hermann Emmanuel E Riveau Gilles G

PloS one 20121031 10

<h4>Background</h4>Pertussis, also known as whooping cough, is a vaccine-preventable respiratory disease caused by Bordetella pertussis infection, against which Senegalese children are immunized with the diphtheria-tetanus-whole cell pertussis vaccine (DTwP). Seroepidemiology of pertussis has been widely described in industrialized countries, but rare are the studies referring to it in developing countries.<h4>Methods</h4>We conducted a longitudinal survey in Northern Senegal to investigate the ...[more]

PMID: 23119090

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Project description:BackgroundPertussis (whooping cough) is well known to be underreported, particularly among adults, who can act as an infectious reservoir, potentially putting susceptible newborns at risk of serious illness. The purpose of this study was to estimate the seroprevalence of pertussis in adults in Hungary.MethodsThis epidemiological, cross-sectional study was conducted in adults in five general practitioners' practices in Hungary. Serum anti-pertussis toxin immunoglobulin G (anti-PT IgG) antibody levels were analyzed using enzyme-linked immunosorbent assay. Sera were classified following manufacturer's instructions as: strongly indicative of current/recent infection (≥1.5 optical density [OD] units); indicative of current/recent infection (≥1.0 OD units); seropositive (>0.3 OD units); or seronegative (≤0.3 OD units). Logistic regression was performed to describe the associations between seroprevalence and various characteristics.ResultsBetween 24th April 2014 and 24th April 2015, 1999 adults (60.6% female; mean age 47.4 ± 17.7 years) were included in the analysis. A total of 14.8% were seropositive for anti-PT IgG, 1.1% had a level indicative of current/recent infection, and 0.1% had a level strongly indicative of current/recent infection. Logistic regression showed significant relationships between increased rates of seropositivity and: age ≥60 years (odds ratio [OR], 1.97; 95% confidence interval [CI], 1.39-2.80; p = .0002) or 18-29 years (OR, 1.67; 95% CI, 1.13-2.46; p = .0094) vs. 45-59 years; former smoker (OR, 1.46; 95% CI, 1.08-1.97; p = .014) or current smoker (OR, 1.38; 95% CI, 1.01-1.89; p = .045) vs. never smoker; and male (OR, 1.30; 95% CI, 1.01-1.68; p = .041) vs. female. Also, between increased rates of probable current/recent infection and current smoker (OR, 7.50; 95% CI, 2.32-24.31; p = .0008) or former smoker (OR, 4.07; 95% CI, 1.21-13.64; p = .023) vs. never smoker.ConclusionsApproximately 85% of the adults studied were seronegative and therefore susceptible to pertussis infection. Approximately 1% had anti-PT IgG levels indicative of current/recent pertussis infection, which could potentially be transmitted to susceptible young infants. Vaccination of adults is a key way to indirectly protect infants.Trial registrationClinical Trials.gov NCT02014519 . Prospectively registered 12 December 2013.

Project description:OBJECTIVES:The primary objective of this study was to compare the 12-month continuation rate for women who self-injected subcutaneous depot-medroxyprogesterone acetate (DMPA-SC) with that for women receiving intramuscular depot-medroxyprogesterone acetate (DMPA-IM) from a provider. This research contributes to the broader goal of identifying solutions to support women to use contraception for their full desired duration. STUDY DESIGN:Participants were clients from 13 clinics in the Dakar and Thiés regions of Senegal who had decided to use injectable contraception prior to enrollment. They chose self-injection of DMPA-SC or provider administration of DMPA-IM. Self-injectors were trained and given three units of DMPA-SC. The provider-injected group received DMPA-IM and returned to the clinics for future injections. We interviewed participants at baseline and after the second, third and fourth injections (the equivalent of 12?months of contraceptive coverage). We employed Kaplan-Meier methods to estimate continuation probabilities, with a log-rank test to compare differences between groups. A multivariate Cox regression identified factors correlated with discontinuation. RESULTS:The 12-month continuation rate for 650 women self-injecting DMPA-SC was 80.2%, while that for 649 women receiving DMPA-IM from a provider was 70.4% (p<.01). The difference in continuation between self-injectors and those receiving DMPA from a provider remained significant in a multivariate Cox regression model. The primary reason for discontinuation in both groups (44.7% self-injected; 44.5% provider-injected) was forgetting to reinject or reinjecting late. Fewer women reported side effects in the self-injection group than in the provider-administered group. CONCLUSIONS:The higher 12-month continuation rate for women self-injecting DMPA-SC relative to provider-administered DMPA-IM suggests that self-injection may help prevent pregnancy more consistently and continuously. IMPLICATIONS:Discontinuation of injectable contraception among women wishing to avoid pregnancy may increase unmet need in francophone West Africa. This study showed higher 12-month continuation rates for women who self-injected DMPA-SC, suggesting that this delivery method may improve injectable continuation.

Project description:BackgroundPertussis remain a global health concern, especially in infants too young to initiate their vaccination. Effective vaccination and high coverage limit the circulation of the pathogen, yet duration of protection is limited and boosters are recommended during a lifetime. In Iran, boosters are given at 18 months and 6 years old using whole pertussis vaccines for which efficacy is not known, and pertussis surveillance is scant with only sporadic biological diagnosis. Burden of pertussis is not well understood and local data are needed.MethodsHospital-based prospective study implementing molecular laboratory testing in infants aged ≤6 months and presenting ≥5 days of cough associated to one pertussis-like symptom in Tehran. Household and non-household contact cases of positive infants were evaluated by comprehensive pertussis diagnosis (molecular testing and serology) regardless of clinical signs. Clinical evaluation and source of infection were described.ResultsA total of 247 infants and 130 contact cases were enrolled. Pertussis diagnosis result was obtained for 199 infants and 104 contact cases. Infant population was mostly < 3 months old (79.9%; 157/199) and unvaccinated (62.3%; 124/199), 20.1% (40/199) of them were confirmed having B. pertussis infection. Greater cough duration and lymphocyte counts were the only symptoms associated to positivity. Half of the contact cases (51.0%; 53/104) had a B. pertussis infection, median age was 31 years old. A proportion of 28.3% (15/53) positive contacts did not report any symptom. However, 67.9% (36/53) and 3.8% (2/53) of them reported cough at inclusion or during the study, including 20.8% (11/53) who started coughing ≥7 days before infant cough onset. Overall, only five samples were successfully cultured.ConclusionThese data evidenced the significant prevalence of pertussis infection among paucy or poorly symptomatic contacts of infants with pertussis infection. Widespread usage of molecular testing should be implemented to identify B. pertussis infections.

Dataset Information

Seroprevalence of pertussis in Senegal: a prospective study.

Background

Methods

Principal findings

Conclusions

Publications

Seroprevalence of pertussis in Senegal: a prospective study.

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