Page 87 - Preventing pertussis in early infancy - Visser

Introduction
Pertussis can be a severe disease, especially for young infants. Infants are vulnerable to severe complications (e.g. apnoea, convulsions) or even death and are not adequately protected by their childhood vaccinations until after they are six months old (Kilgore et al. 2016). Many countries have reported a resurgence of pertussis in recent decades, despite childhood vaccination programmes with high uptake rates (Burns et al. 2014, Miller 2014). A Dutch serosurveillance study found antibodies suggestive of a recent pertussis infection in one in ten adults, although most of them never noticed the infection, as pertussis can present itself as a common cold in adults (de Greeff et al. 2010). This increased pertussis incidence has not only caused pertussis in infants and adults, but also led to multiple pertussis outbreaks in healthcare settings (including neonatal care) (Leekha et al. 2009, Maltezou et al. 2013, Heininger 2014). In the reported pertussis outbreaks in healthcare settings, HCWs turned out to be either the introductory source and/or part of the transmission chain (Leekha et al. 2009, Maltezou et al. 2013, Heininger 2014).
In order to prevent pertussis in infants, several pertussis booster vaccination programmes have been developed to prevent transmission to the most vulnerable groups either indirectly (pertussis cocooning, i.e. vaccinating those surrounding an infant) or more directly (maternal pertussis vaccination, i.e. vaccinating pregnant women in the third trimester of their pregnancy) (Wirsing von Konig et al. 2005, Miller 2014). In the context of cocooning, pertussis vaccination has also been advised for healthcare workers (HCWs), aiming to prevent transmission of pertussis and pertussis outbreaks in healthcare settings (Commission 2000, Wirsing von Konig et al. 2005, Miller 2014). More specifically, HCW pertussis vaccination is recommended for high-income countries by the WHO and the global pertussis initiative and is in line with the European legislation on occupational health risks of biological agents (Commission 2000, Wirsing von Konig et al. 2005, Miller 2014). Furthermore, many high-income countries (including several European countries) adapted their national policies and now recommend pertussis vaccination either for all HCWs or specific groups of HCWs (Kretsinger et al. 2006, Maltezou et al. 2014). There is no direct empirical evidence of this strategy’s efficacy on the reduction of morbidity or mortality in children, (Rivero-Santana et al. 2014) but modelling studies suggest that implementation of an immunisation programme with at least 25% coverage provides both greater health and greater economic benefits than having no vaccination programme (Greer et al. 2011). Despite the recommendations, vaccination uptake rates are low among HCWs who work with infants, ranging from 11%-85% (Peadon et al. 2007, Guthmann et al. 2012, Mir et al. 2012, Lu et al. 2014, MacDougall et al. 2015, Ryser et al. 2015, Tuckerman et al. 2015, Walther et al. 2015, Harrison et al. 2016, Maltezou et al. 2016, Paranthaman et al. 2016). Studies describing determinants of HCW pertussis vaccination acceptance find that the perceived risk of pertussis, previous vaccination acceptance, and knowledge about the vaccination programme are important correlates of the motivation to vaccinate (Goins et al. 2007, Peadon et al. 2007, Calderon et al. 2008, Wicker et al. 2008, Top et al. 2010, Baron-
Intervention Mapping
Intervention Mapping
89
85