Research and analysis

Parvovirus B19 activity in England to July 2024

Updated 29 August 2024

Applies to England

Parvovirus B19 causes the common childhood illness, erythema infectiosum aka fifth disease (1) – widely known as “slapped cheek” due to the typical presentation of erythematous cheeks in children which, together with rash and fever, are characteristic of this disease. Accurate diagnosis on a clinical basis can be difficult, however, and parvovirus B19 infection cannot be clearly differentiated from other infections such as rubella. Parvovirus B19 is seasonal with highest activity usually seen in spring and early summer with cyclical peaks every 3 to 4 years, predominantly in school-aged children. In recent years cyclical increases have persisted across 2 consecutive years.

Whilst there had been low activity since 2018, reported cases of parvovirus B19 began to increase at the end of 2023 and beginning of 2024. The European Centre for Disease Prevention and Control (ECDC) similarly reported an increase in parvovirus B19 detections across 9 other European countries (1).

Activity to June 2024 surpassed the levels seen in the most recent previous peak years in 2017 and 2018. Based on cases confirmed by the UK Health Security Agency (UKHSA) Colindale Reference laboratory in women of child-bearing age (15 to 44 years), 2017 and 2018 peaked respectively at 43 and 46 cases in May, compared to 73 cases in June 2024 (Figure 1). In line with patterns in previous periods of high activity, case numbers declined in July 2024 with 36 cases (provisional data) reported among this age group of women.

Parvovirus B19 is not a notifiable disease and testing practice is likely to vary around the country. Except for women in contact with or presenting with a rash illness in pregnancy (UKHSA Rash in Pregnancy guidance), there is no recommendation for routine laboratory testing for parvovirus B19. Confirmation of recent infection is by detection of parvovirus B19-specific IgM and/or a high parvovirus viral load (> 10,000 IU/ml, (2)).

Infection in the first 20 weeks of pregnancy is associated with increased risk of intrauterine death and hydrops fetalis. Infection usually presents as a mild febrile illness but in patients with increased red blood cell turnover (for example, underlying haemolytic haemoglobulinopathies such as sickle cell disease) infection can lead to transient aplastic crisis, and in patients who are immunocompromised infection may lead to pure red cell aplasia and chronic anaemia. Both these groups of patients have very high levels of viraemia and should be considered infectious. Health Protection Teams and clinicians should be aware that there are National Institute for Health and Care Excellence (NICE) Clinical Knowledge Summaries (3) and national guidelines for managing the infection in healthcare settings, the community (4) and in pregnant women (5).

Figure 1.  Monthly laboratory confirmed reports of parvovirus B19 infection in women aged 15 to 44 years: January 2017 to July 2024 (England only, provisional data)

References

1. European Centre for Disease Prevention and Control Risks posed by reported increased circulation of human parvovirus B19 in the EU/EEA, 5 June 2024. ECDC: Stockholm; 2024 
2. Maple PA, Hedman L, Dhanilall P, Kantola K, Nurmi V, Soderlund-Venermo M, and others. Identification of past and recent parvovirus B19 infection in immunocompetent individuals by quantitative PCR and enzyme immunoassays: a dual-laboratory study) Journal of Clinical Microbiology, 2014.
3. NICE Clinical Knowledge Summaries: Parvovirus B19 infection.
4. Crowcroft NS, Roth CE, Cohen BJ, Miller E. Guidance for control of Parvovirus B19 infection in healthcare settings and the community. Journal of Public Health, 1999.
5. UKHSA, Viral rash in pregnancy guidance.