Research and analysis

Laboratory confirmed cases of pertussis in England: January to March 2022

Updated 23 May 2024

Applies to England

In England, there were 9 laboratory confirmed cases of pertussis (culture, PCR, serology or oral fluid) reported to the UK Health Security Agency (UKHSA) pertussis enhanced surveillance programme in the first quarter of 2022, from January to March (table 1). Total case numbers were 18% lower than those reported in same quarter of 2021 (11 cases) and considerably lower than the 806 cases reported in this period in 2020 (see Figure 1).

The coronavirus (COVID-19) pandemic and the implementation of social distancing measures and lockdown across the UK from 23 March 2020 had a significant impact on the spread and detection of other infections including pertussis. From July 2021 COVID-19 containment measures were withdrawn in England. Vaccination continues to be important as levels of disease are likely to increase following the easing of control measures.

Overall pertussis activity has declined since measures to control the spread of COVID-19 were introduced. The number of confirmed cases in infants under 3 months, who are targeted by the maternal immunisation programme, continues to remain extremely low with no confirmed cases in this quarter compared to 0 and 16 cases in the same quarters in 2021 and 2020, respectively.

There were no confirmed cases in infants aged between 3 and 11 months, consistent with protection from primary vaccination offered at 2, 3 and 4 months of age. There were 2 confirmed cases in children aged between 1 and 4 years compared to 0 and 36 cases in 2021 and 2020, respectively . Overall there were no cases in infants aged less than one year in the first quarter of 2022 compared to 1 and 27 in the equivalent quarters in 2021 and 2020 respectively (table 2).

Between January and March 2022, 7 of the 9 cases of laboratory confirmed pertussis in England occurred in individuals aged 15 years or older. The total in this age group was also low in the same period in 2021 at 10 cases, compared to 578 cases in January to March 2020.

Guidelines for the public health management of pertussis provide details on the appropriate laboratory investigation of suspected cases of pertussis which is informed by the age of the suspected case and time since onset of their symptoms.

Deaths

There were no reported deaths in infants with pertussis confirmed January and March 2022. The last pertussis-related death of an infant was reported in the second quarter (April to June) of 2019. Calculated maternal vaccine effectiveness against death of infants from pertussis is very high at around 95% (1).

Childhood vaccination programme

The national vaccination schedule recommends pertussis vaccination at 8, 12 and 16 weeks of age and a pre-school booster at 3 years and 4 months.

Vaccine coverage estimates (evaluated between January and March 2022) for DTaP/IPV/Hib/HepB immunisation across England was 91.9% for 3 doses at 12 months of age and 84.6% for the booster dose by 5 years of age (2). Coverage estimates at 12 months of age were slightly higher than the coverage estimates for January to March 2021 when the proportion of children vaccinated at 12 months was 91.6% and coverage estimates for the booster dose were lower than the 85.1% reported (3).

The introduction of social distancing in response to the COVID-19 pandemic from late March 2020, when some of this cohort would have been scheduled for vaccination, may have contributed to the modest decrease seen in the booster dose coverage.

Maternal vaccination programme

The maternal pertussis immunisation programme introduced in response to the 2012 outbreak (4, 5) became permanent from June 2019 (6) based on evidence of disease impact, high effectiveness and safety (1, 7, 8, 9). The recommended gestational age for vaccination is between 20 and 32 weeks, ideally after the 20-week scan, but the vaccine can be given as early as 16 weeks for pragmatic reasons to ensure vaccination (6).

Monthly pertussis vaccine coverage was 64.3% in January, 64.2% in February and 63.4% in March 2022. The mean coverage for the quarter was 64.0%, which was 2.8 percentage points lower than mean coverage for the same quarter in 2021 (10). This observed decline in coverage has largely been driven by a decrease in London NHS Commissioning Region which had coverage that was 12.9 percentage points lower in March 2022 as compared to March 2020.

The impact of the pandemic on healthcare services has possibly resulted in vaccine coverage this quarter being lower than any previous January to March coverage estimates since 2017. This could be due to a potential increase in the delivery of the vaccines through maternity units, during the pandemic, which may not have been captured completely in the survey and therefore resulted in an underestimation of coverage.

Surveillance data in young infants following the introduction of the pertussis immunisation in pregnancy programme demonstrated that a low incidence had been maintained in this age group, with expected seasonal increases. COVID-19 control measures appear to have had an additional impact on these observed effects. It is therefore important that women continue to be supported to access immunisation against pertussis during pregnancy (ideally between 20 and 32 weeks) to optimise protection for their babies from birth.

Table 1. Laboratory-confirmed cases of pertussis by age and testing method * in England, January to March 2022 *

Age group Culture PCR Serology Oral fluid only Total
Less than 3 months 0 0 0 0 0
3 to 5 months 0 0 0 0 0
6 to 11 months 0 0 0 0 0
1 to 4 years 0 0 0 2 2
5 to 9 years 0 0 0 0 0
10 to 14 years 0 0 0 0 0
15 years and over 0 0 7 0 7
Total 0 0 7 2 9

*Culture-confirmed cases may additionally have tested positive by any other method; PCR-confirmed cases may have additionally tested positive by serology or OF; and serology-confirmed cases may also have been confirmed by OF. Cases are only represented once in the table.

Figure 1. Total number of laboratory-confirmed pertussis cases per quarter in England, 2011 to 2022

Table 2. Laboratory-confirmed cases of pertussis by age and year in England, October to December: 2012 to 2022

Age group 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022
Less than 3 months 70 26 12 16 35 31 9 12 16 0 0
3 to 5 months 11 7 5 6 9 6 4 7 8 1 0
6 to 11 months 2 0 3 2 5 0 4 4 3 0 0
1 to 4 years 4 20 6 14 15 11 13 16 36 0 2
5 to 9 years 13 29 24 39 77 37 30 44 44 0 0
10 to 14 years 98 175 79 82 121 89 65 92 121 0 0
15 years and over 504 1,368 473 622 1,002 722 522 429 578 10 7
Total 702 1,625 602 781 1,264 896 647 604 806 11 9

References

1. Amirthalingam G and others (2016) ‘Sustained effectiveness of the maternal pertussis immunization program in England three years following introduction’, Clinical Infectious Diseases

2. Quarterly vaccination coverage statistics for children aged up to 5 years in the UK (COVER programme): January to March 2022. Health Protection Report volume 16 number 6, 28 June 2022

3. Quarterly vaccination coverage statistics for children aged up to 5 years in the UK (COVER programme): January to March 2022. Health Protection Report volume 15 number 11, 29 June 2021

4. Confirmed pertussis in England and Wales continues to increase (2012). Health Protection Report volume 6 number 15

5. Department of Health (2012) ‘Pregnant women to be offered whooping cough vaccine’ (website news story, 28 September)

6. Joint Committee on Vaccination and Immunisation minutes

7. Amirthalingam G and others (2014) ‘Effectiveness of maternal pertussis vaccination in England: an observational study’, The Lancet

8. Dabrera G and others (2014) ‘A case-control study to estimate the effectiveness of maternal pertussis vaccination in protecting new-born infants in England and Wales, 2012–2013’, Clinical Infectious Diseases

9. Donegan K and others (2014) ‘Safety of pertussis vaccination in pregnant women in UK: observational study’, British Medical Journal

10. Pertussis vaccination programme for pregnant women update: vaccine coverage in England, January to March 2022. Health Protection Report volume 16 number 8 (23 August 2022)