Årsrapporten för övervakningen av kikhosta (pertussis) beskriver utfallet av antal rapporterade fall av kikhosta för alla åldersgrupper med förstärkt övervakning av kikhosta hos barn och ungdomar som pågått i Sverige under tjugoett års tid. Rapporten beskriver i detalj förekomst av kikhosta utifrån ålder, vaccinationsstatus och sjukdomsbörda med särskilt fokus på barn yngre än ett år. Rapporten är avsedd som kunskapsstöd för forskare och vårdgivare. Målgruppen för årsrapporten är hälso- och sjukvårdspersonal, och då särskilt personal inom mödravård, barnhälsovård och barnsjukvård samt primärvård och smittskyddsenheter.
During 2018, 715 laboratory-confirmed cases of pertussis in all ages were reported, of which 68 cases were among infants younger than one year of age. This 21st annual report enhanced pertussis surveillance summarises the epidemiology of pertussis in Sweden since the introduction of acellular pertussis vaccine in 1996. The current report will particularly focus on the most vulnerable age group with the highest risk for severe disease - infants (0–12 months of age).
The incidence of pertussis among infants as well as among the population overall has decreased since 1996 when acellular pertussis vaccine was introduced in Sweden. The incidence of pertussis was low during 2009-2013, but the number of reported cases increased threefold in 2014 for all ages. The higher incidence in the population overall has remained, which might partly be due to an increase in the number of samples taken since 2014. There have been no infant deaths due to pertussis since 2015, and both the number of cases among infants and the incidence have had a noteworthy and significantly decreasing trend since 2014. As in previous years infants aged 3 months and younger had the highest incidence of pertussis in 2018 (111/100,000 person years), and the highest rate of hospitalisation and complications due to pertussis. This group of infants, younger than 3 months of age, contracted pertussis before they had received the first dose of vaccine.
The fifth dose of pertussis vaccine was implemented for teenagers 14-16 years of age in 2016. Since then there has been a decreasing trend in the number of reported pertussis cases in this age group. Meanwhile, increasing numbers of pertussis cases among 10-14 year olds have been observed. These trends will continue to be monitored closely since pertussis among 10-14 year olds might be of more importance for the transmission of disease to infants in comparison to that of older teenagers.
Since recommendations aiming to decrease the burden of disease among infants were published in 2016, there has been no decrease in the time between onset of disease and start of antibiotic treatment in infants. The timeliness of the first dose of vaccine has been good both before and after the recommendation.
Despite existing preventive strategies, the age group with highest incidence of pertussis in Sweden was in infants under 3 months of age. To further decrease the incidence in this vulnerable age group, awareness of the disease among caregivers needs to be improved. If an increase in pertussis among infants is observed in the future, other preventive measures and interventions, including recommendation of maternal vaccination, may have to be considered.