Erythema infectiosum affects people worldwide, of any age group (it is most common in children aged 6-10 years), and can occur sporadically throughout the year.[8]UK Health Security Agency. Parvovirus B19: guidance, data and analysis. Aug 2024 [internet publication].
https://www.gov.uk/guidance/parvovirus-b19
Epidemics are common, usually seen in the late winter and early spring and possibly follow a 6-year cycle.[9]Cherry JD. Parvovirus infections in children and adults. Adv Pediatr. 1999;46:245-69.
http://www.ncbi.nlm.nih.gov/pubmed/10645467?tool=bestpractice.com
In the UK, infection peaks in spring and early summer, with 3 to 4 year cycles of increased incidence.[10]Public Health England. Parvovirus B19 activity in England and Wales. May 2019 [internet publication].
https://www.gov.uk/government/publications/parvovirus-b19-activity-in-england-and-wales
Erythema infectiosum presents in up to 10% of paediatric patients, up to 60% of female patients, and up to 30% of male patients.[11]Lowry SM, Brent LH, Menaldino S, et al. A case of persistent parvovirus B19 infection with bilateral cartilaginous and ligamentous damage to the wrists. Clin Infect Dis. 2005 Aug 15;41(4):e42-4.
https://www.doi.org/10.1086/432118
http://www.ncbi.nlm.nih.gov/pubmed/16028146?tool=bestpractice.com
Spread is via direct contact and respiratory droplets, and infection is most common in school-aged children and household contacts. The virus can be transmitted transplacentally from mother to fetus. Spread has also been reported via blood or blood products.[12]Azzi A, Morfini M, Mannucci PM. The transfusion associated transmission of Parvovirus B19. Transfus Med Rev. 1999;13:194-204.
http://www.ncbi.nlm.nih.gov/pubmed/10425692?tool=bestpractice.com
[13]Yu MY, Alter HJ, Virata-Theimer ML, et al. Parvovirus B19 infection transmitted by transfusion of red blood cells confirmed by molecular analysis of linked donor and recipient samples. Transfusion. 2010;50:1712-1721.
http://www.ncbi.nlm.nih.gov/pubmed/20158689?tool=bestpractice.com
Seroprevalence for parvovirus B19 increases with age and by 15 years old, over 50% of adolescents have antiparvovirus antibodies.[9]Cherry JD. Parvovirus infections in children and adults. Adv Pediatr. 1999;46:245-69.
http://www.ncbi.nlm.nih.gov/pubmed/10645467?tool=bestpractice.com
Recent data indicates an increase in parvovirus B19 activity, the virus responsible for erythema infectiosum. Since March 2024, there has been a significant rise in cases reported in 14 European countries, and in August 2024, the US Centers for Disease Control and Prevention (CDC) issued a Health Alert about increased activity in the US. This recent surge in cases has affected all age groups, with the largest increase seen among children aged 5-9 years. Parvovirus B19 is highly transmissible through respiratory droplets and can also be transmitted transplacentally from mother to fetus. Recent reports indicate a higher incidence of infections among pregnant individuals, with an increased number of fetal complications. The maternal-to-fetal transmission rate during acute infection ranges from 17% to 33%, with a 5% to 10% risk of adverse fetal outcomes, particularly if the infection occurs between 9 and 20 weeks of gestation. Additionally, an increased number of cases have been reported in individuals with sickle cell disease, underscoring the virus's impact on vulnerable populations.[14]Centers for Disease Control and Prevenion. Emergency preparedness and response: increase in human parvovirus B19 activity in the United States. Aug 2024 [internet publication].
https://emergency.cdc.gov/han/2024/han00514.asp
[15]European Centre for Disease Prevention and Control. Risks posed by reported increased circulation of human parvovirus B19 in the EU/EEA. Jun 2024 [internet publication].
https://www.ecdc.europa.eu/en/publications-data/risks-posed-reported-increased-circulation-human-parvovirus-b19-eueea
[16]American College of Obstetricians and Gynecologists. Increase in human parvovirus B19 activity in the United States. Aug 2024 [internet publication].
https://www.acog.org/clinical/clinical-guidance/practice-advisory/articles/2024/08/increase-in-human-parvovirus-b19-activity-in-the-united-states