Recent studies have revealed a concerning uptick in cases of parvovirus B19 across the United States, particularly affecting pregnant women and children with sickle cell disease. The findings, published in the Morbidity and Mortality Weekly Report, highlight a significant increase in infections detected in commercial laboratories, with notable clusters identified in Minnesota and Georgia.

In August, the Centers for Disease Control and Prevention (CDC) issued a Health Alert Network advisory in response to the rising number of cases associated with parvovirus B19. This advisory was prompted by reports of lab test positivity and complications related to the virus among vulnerable populations, including pregnant women and individuals with sickle cell disease. Alarmingly, several European countries had already reported similar surges in B19 activity earlier in 2024.

Parvovirus B19 is known to increase the risk of miscarriage, particularly in the early stages of pregnancy. The symptoms of the illness can manifest as a distinctive “slapped-cheek” rash in children and joint pain in adults. While many cases are mild or asymptomatic, individuals with pre-existing blood disorders or compromised immune systems may face more severe health consequences.

According to the authors of the lab study, the transmission of B19 can occur from a mother to her fetus during pregnancy. Additionally, the virus can be transmitted, albeit rarely, through blood transfusions and certain plasma derivatives. Most individuals contract B19 during their school years, and once infected, they typically develop lifelong immunity.

The first of the three studies examined the surge in parvovirus B19 test positivity at Labcorp, a major laboratory services provider, in collaboration with the CDC. The research team analyzed clinical specimens from 359,445 children and adults, focusing on the presence of immunoglobulin M (IgM) antibodies, which indicate recent infection. They also conducted nucleic acid amplification testing (NAAT) on plasma from an average of 1,059 donor pools each month.

Healthcare providers caring for pregnant individuals are being urged to remain vigilant for signs of reduced fetal movement or severe swelling, known as hydrops, which may be associated with B19 infection. The analysis revealed that the percentage of IgM-positive clinical specimens surged to 9.9% in spring 2024, a significant increase from less than 1.5% recorded between 2020 and 2023. This figure also surpassed previous peaks observed in 2018 (3.8%) and 2019 (5.1%).

Furthermore, the prevalence of B19-NAAT-positive plasma donor pools rose dramatically to 20% in June 2024, compared to less than 2% in the same timeframe from 2020 to 2023. This increase also exceeded the peaks recorded in spring 2018 (6.7%) and 2019 (7.3%). The data suggests a heightened level of community transmission of parvovirus B19 in 2024, raising concerns among health officials.

As parvovirus B19 continues to circulate, public health experts emphasize the importance of awareness and monitoring, particularly among at-risk populations. The rise in infections underscores the need for healthcare providers to be proactive in identifying and managing cases, especially in pregnant women and children with vulnerable health conditions.

In light of these findings, continued surveillance and research into the epidemiology of parvovirus B19 will be crucial in mitigating the impact of this virus on public health. The CDC and other health authorities are likely to implement strategies aimed at reducing transmission and protecting those most at risk.

Overall, the recent spike in parvovirus B19 cases serves as a reminder of the ongoing challenges posed by infectious diseases, highlighting the need for vigilance, education, and proactive healthcare measures to safeguard the health of the community.