A seasonal respiratory virus known as parvovirus B19, also referred to as fifth disease, is showing increased activity, according to a recent alert from the US Centers for Disease Control and Prevention (CDC).
Parvovirus B19 is a common virus that spreads through respiratory droplets. The CDC notes that antibodies developed from previous infections may offer protection against reinfection, with about half of US adults having detectable levels of these antibodies by age 20, and over 70% by age 40. Individuals in occupations involving close contact with children, such as in schools and daycares, are at higher risk of infection.
Efforts to curb the spread of Covid-19 during the pandemic led to a significant decrease in parvovirus B19 infections, resulting in a decline in immunity levels.
The CDC's Health Alert Network issued an advisory reporting an uptick in test positivity rates and clusters of complications among high-risk individuals. Recent data showed a rise in the proportion of people with antibodies indicating recent infection, particularly among children aged 5 to 9.
Anecdotal reports received by the CDC highlighted an increase in cases among pregnant individuals, with some experiencing severe complications like fetal anemia or miscarriage, as well as a rise in aplastic anemia cases in individuals with sickle cell disease.
While many individuals infected with parvovirus B19 may not exhibit symptoms, those who do typically experience two phases of illness. The initial phase, occurring about a week post-infection, presents symptoms such as fever, muscle aches, and malaise. The contagious period is most significant during this phase.
In the subsequent phase, which begins approximately a week later, children often develop a distinctive facial rash known as a slapped cheek rash, followed by a body rash or joint pain. Adults may experience a trunk rash and joint pain.
Severe complications from parvovirus can arise in specific groups, including individuals with chronic hemolytic conditions like sickle cell disease or those with compromised immune systems, who may develop aplastic anemia. Pregnant individuals face potential adverse fetal outcomes in 5% to 10% of cases, such as anemia, hydrops, or miscarriage.
There is currently no vaccine for parvovirus, and treatment focuses on symptom management, as most infections resolve on their own.
As cases of parvovirus B19 increase, the CDC advises the public to adhere to general precautions for preventing respiratory illnesses, such as frequent handwashing, maintaining clean surfaces, and practicing proper respiratory etiquette. Individuals experiencing symptoms should isolate themselves until symptoms improve and they have been fever-free for at least 24 hours without medication.
For pregnant individuals, those with weakened immune systems, or individuals with chronic hemolytic disorders, the CDC recommends wearing a mask around others and seeking prompt medical attention if symptoms develop.
