Page 10 - Preventing pertussis in early infancy - Visser

Chapter 1
Chapter 1
Introduction
Despite an overall high uptake of childhood vaccinations, pertussis has changed in the last two decades from a marginalised childhood disease to an endemic disease among adolescents and young adults. Although for adults pertussis is mostly a nuisance, it can be a dangerous disease for infants who are too young to be fully protected by their own childhood vaccinations. To reduce the burden of pertussis in infants, several policies were evaluated and proposed. Pertussis cocooning (i.e. vaccination of all adults surrounding an infant) and selective pertussis vaccination of healthcare workers (HCWs) who work with infants are such strategies. These strategies contribute to the prevention of pertussis transmission to newborn babies. For an effective implementation of these strategies, most theories on behavioural change emphasise that it is essential to recognise that individual people function in a complex environment, where in addition to their personal d d e e t t e e r r m m i i n n a a n n t t s s , , d d i i f f f f e e r r e e n n t t s s o o c c i i a a l l a a n n d d p p h h y y s s i i c c a a l l c c o o n n d d i i t t i i o o n n s s a ar r e e r r e e l l e e v v a a n n t t . . C C o o n n s s e e q q u u e e n n t t l l y y , , a a vaccination programme should take account of a broad array of determinants that influence the vaccination acceptance in the target groups.
In this thesis, we set out to explore these determinants by qualitatively and quantitatively assessing the potential factors governing the pertussis cocooning acceptance among envisioned target groups. Using an Intervention Mapping approach, we subsequently designed a pilot vaccination programme by taking the most relevant and changeable determinants into account. In the next paragraphs we will introduce pertussis, the rationale for pertussis cocooning and selective pertussis vaccination for HCWs. This is followed by a background on implementation methodology, which is needed when aiming to introduce an effective vaccination strategy. Finally, the thesis objectives and outline are laid out.
Pertussis
Clinical manifestation
Pertussis, or whooping cough, is a respiratory disease caused by the bacterial species Bordetella. Most pertussis patients suffer from an infection with B. pertussis and to a lesser extent from an infection with B. parapertussis. Typically, a pertussis infection starts with the symptoms associated with a common cold: a runny nose, a mild occasional cough, sometimes a low-grade fever and a feeling of malaise. In this catarrhal stage, pertussis is highly contagious, with a secondary attack rate of up to 90% among non-immune household contacts (Heininger 2001, Crowcroft et al. 2006, Miller 2014, Plotkin et al. 2018). After one or two weeks, in the paroxysmal stage, the traditional symptoms of pertussis appear: paroxysms (fits) of many, rapid coughs followed by a high-pitched “whoop” sound at inhalation, after which vomiting and exhaustion can occur. After this, in the convalescent stage, the cough gradually gets milder, but can last for several weeks before complete recovery (Crowcroft et al. 2006, Kilgore et al. 2016). A pertussis infection induces antibodies that can be used for diagnostic purposes, but these are unable to provide long-lasting
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