Dépistage familial systématique dans la coqueluche du nourrisson

Asymptomatic Infection and Transmission of Pertussis in Households: A Systematic Review

We conducted a systematic review to describe the frequency of mild, atypical, and asymptomatic infection among household contacts of pertussis cases and to explore the published literature for evidence of asymptomatic transmission. We included studies that obtained and tested laboratory specimens from household contacts regardless of symptom presentation and reported the proportion of cases with typical, mild/atypical, or asymptomatic infection. After screening 6789 articles, we included 26 studies. Fourteen studies reported household contacts with mild/atypical pertussis. These comprised up to 46.2% of all contacts tested. Twenty-four studies reported asymptomatic contacts with laboratory-confirmed pertussis, comprising up to 55.6% of those tested. Seven studies presented evidence consistent with asymptomatic pertussis transmission between household contacts. Our results demonstrate a high prevalence of subclinical infection in household contacts of pertussis cases, which may play a substantial role in the ongoing transmission of disease. Our review reveals a gap in our understanding of pertussis transmission.

Strategies to decrease pertussis transmission to infants

The Global Pertussis Initiative (GPI) is an expert scientific forum addressing the worldwide burden of pertussis, which remains a serious health issue, especially in infants. This age cohort is at risk for developing pertussis by transmission from those in close proximity. Risk is increased in infants aged 0 to 6 weeks, as they are too young to be vaccinated. Older infants are at risk when their vaccination schedules are incomplete. Infants also bear the greatest disease burden owing to their high risk for pertussis-related complications and death; therefore, protecting them is a high priority. Two vaccine strategies have been proposed to protect infants. The first involves vaccinating pregnant women, which directly protects through the passive transfer of pertussis antibodies. The second strategy, cocooning, involves vaccinating parents, caregivers, and other close contacts, which indirectly protects infants from transmission by preventing disease in those in close proximity. The goal of this review was to present and discuss evidence on these 2 strategies. Based on available data, the GPI recommends vaccination during pregnancy as the primary strategy, given its efficacy, safety, and logistic advantages over a cocoon approach. If vaccination during pregnancy is not feasible, then all individuals having close contact with infants <6 months old should be immunized consistent with local health authority guidelines. These efforts are anticipated to minimize pertussis transmission to vulnerable infants, although real-world effectiveness data are limited. Countries should educate lay and medical communities on pertussis and introduce robust surveillance practices while implementing these protective strategies.

Improving adherence rates to a cocooning program: a pilot experience in Italy

Cocoon is defined as a strategy to reduce the risk for transmission of pertussis to newborn infants by vaccinating household members including parents and siblings. Programmatic challenges make implementation of cocooning program complex. At the local health care unit “ASL Napoli 1 Centro,” a one-year pilot project to evaluate the newborn contacts adherence to a cocoon strategy was started on May, 1st 2011. Healthcare providers (HCPs) offered for free a dTpa booster dose to newborns parents (mothers were immunized after delivery) and household contacts. Until June 30th, overall only 7 dTpa booster doses out of 261 newborns (2.6%) were administered for cocooning. Then, an improvement in communication strategy to the families was introduced by preparing specific information leaflets, increasing the HCPs devoted to the cocoon, and focusing the interaction with families during the visiting time at the maternity ward. Overall, 601 out of 762 (78,8%) contacted new mothers received dTpa booster. Cocoon high acceptance rates could be reached providing that proper communication tools and enough skilled HCPs were engaged in the interaction with the families. This report is, to our knowledge, the first to document successful implementation of pertussis cocooning in an Italian setting.

[Pertussis vaccination for parents: proposal and evaluation of two professional practices in a maternity hospital]

BACKGROUND

Despite good rates of immunization among children, an apparent increase in the incidence of pertussis disease in infants in France has been observed, mainly because of low vaccination coverage among adults. Guidelines drawn up in 2004 recommend a vaccination strategy called cocooning for parents, but those guidelines are rarely followed by the medical community. Raising the vaccination rate among parents to 65% and the extension of pertussis vaccine booster for people between 26 and 28 years old could help control the disease.

OBJECTIVE AND METHODS

In a primary healthcare setting in 2009, we studied 2 groups of 188 and 190 parents of newborns in a maternity unit. We proposed 2 strategies: information and vaccine prescription for both parents (if eligible) at the time of discharge from the maternity unit (group 1) or vaccination proposed to both parents during hospitalization in the maternity unit (group 2). After 6 weeks, the vaccination rates of both groups were compared.

RESULTS

Analysis shows that parents had insufficient knowledge of the disease. Parents were often unaware of their vaccination status. Hence, objective data concerning the vaccination status was quickly available for only 42% of the population, making determination of eligibility unreliable. Only 8% of the parents were up to date for pertussis vaccination in the last 10 years, whereas 90% of the parents had the opportunity for vaccination and 37% of them had been eligible before the pregnancy. At the end of the study, 53% of the parents in group 1 were vaccinated, showing the positive impact of the medical encounter and vaccine prescription. During the study, 40% of the parents in group 2 who were proposed immediate vaccination in the maternity unit accepted it. This increased to 43% of group 2 parents being immunized by the time they had left the maternity unit. Proposing the vaccination at the maternity hospital was the more effective of the 2 strategies (P=0.03): at the end of the study, the objective was nearly reached with 64% of the parents being vaccinated.

CONCLUSIONS

The promotion of parental vaccination by the pediatrician in the maternity ward is simple and effective. Medical encounters resulting from prescriptions made during hospitalization could raise awareness in general practitioners and enable them to identify eligible adults for pertussis vaccination and vaccinate themselves. There is a need to discuss the complementarity and interactions between perinatal teams and general practitioners within the community healthcare network.