There were 3681 laboratory-confirmed cases of pertussis (culture, polymerase chain reaction, serology or oral fluid) reported to the Public Health England pertussis enhanced surveillance programme in 2019, the newly published annual report shows.
The 2019 figures included one infant death and were 25 per cent higher than the 2948 cases of pertussis reported in 2018.
The national incidence for all age groups, based on laboratory confirmations in England and 2018 population estimates, was 7/100,000 in 2019 compared with 5/100,00 in the previous year and 8/100,000 in 2017; it had reached 18/100,000 in 2012 (epidemic peak year). Prior to the major peak in 2012, incidence ranged between 0.4/100,000 and 2/100,000.
Laboratory-confirmed pertussis cases in infants aged under one year were 48 per cent higher in 2019 (136 cases) than in 2018 (92 cases). This compares with 508 confirmed cases reported in 2012. There has been a decline in pertussis incidence in infants under three months of age since the introduction of the maternal vaccination programme, from 234/100,000 in 2012 to 93/100,000 in 2016 and 52/100,000 in 2019.
The number of confirmed cases in infants less than three months of age in 2019 was 69 per cent higher (83 cases) than in 2018 when 49 cases were reported, the lowest number of confirmed cases since the introduction of enhanced surveillance in 1994. The incidence does, however, remain highest in infants aged less than three months, who are at most risk for severe disease and too young to be fully vaccinated.
Annual maternal pertussis vaccine coverage for the financial year 2018/2019 was 68.8 per cent, 3.1 percentage points lower compared with 2017/2018. "The decrease could represent a genuine decrease, or a shift from vaccination in general practice to vaccination in maternities which are not always recorded in primary care records," the report noted.