Parvovirus B19 Antibodies, IgG & IgM

Parvovirus B19 is a seasonal respiratory virus that is transmitted by respiratory droplets from people with either symptomatic or asymptomatic infection. Parvovirus B19 is highly transmissible with 50% of susceptible people infected after household exposure and more than 20% of susceptible students and staff infected during school outbreaks. More than 70% of adults have detectable antibodies by age 40 years. Antibodies formed during prior infection are thought to be protective agains reinfection. 

Although some people with parvovirus B19 infection are asymptomatic, immunocompetent children and adults typically develop a biphasic illness. The first phase of illness develops approximately 7 days after infection and is characterized by symptoms of fever, myalgia, and malaise. This phase lasts approximately 5 days. People with parvovirus B19 infection are most contagious during the first phase, when viral loads in respiratory secretions and saliva are highest. The second phase occurs approximately 7 to 10 days after the first phase. Children often develop a characteristic facial rash that is described as a slapped cheek appearance. Within the next 1 to 4 days, children may develop body rash or arthralgia. Medically, this phase is termed erythema infectiosum or fifth disease. 

In immunocompetent adults, the most common symptoms of parvovirus B19 disease typically occur during the second phase and include a reticular rash on the trunk and arthralgia. Typically, the characteristic facial rash does not appear until after viral loads have declined. 

Laboratory tests conducted during acute illness can demonstrate a transient decrease in absolute reticulocyte counts lasting approximately 10 days, mild anemia, thrombocytopenia, or leukopenia. Most people require only supportive care during the acute phase of illness and will recover completely. 

Parvovirus B19 infection can lead to adverse health outcomes among people without pre-existing immunity who are pregnant, immunocompromised, or have chronic hemolytic disorders. 

During pregnancy, most cases of fetal parvovirus B19 infection resolve spontaneously without adverse outcomes. However, transplacental fetal infection occurs in approximately 30% of women infected during pregnancy. Approximately 5 to 10% of these pregnancies experience an adverse fetal outcomes such as fetal anemia, non-immune hydrops fetalis, intrauterine growth retardation, or fetal loss. The risk of an adverse outcome is highest when acute infection occurs between gestational weeks 9 and 20. Treatment for acute infection in the pregnant individual is supportive, and management includes monitoring for and treating severe fetal anemia. 

Parvovirus B19 can cause chronic or transient pure red cell aplasia among people who are severely immunocompromised due to leukemia, other cancers, organ transplant, HIV infection, and chemotherapy. Bone marrow biopsy reveals giant proerythroblasts with viral inclusions.  

Parvovirus B19 preferentially replicates in human erythroid progenitor cells. Transient aplastic crisis is usually seen in patients with chronic hemolytic disorders such as sickle cell anemia, thalassemia, and hereditary spherocytosis. Infection causes an abrupt cessation of erythropoiesis and anemia that lasts up to 8 days. Severe anemia can be life threatening in these patients. Red blood cell transfusions and intravenous immunoglobulin are the mainstays of treatment for aplastic anemia.

Diagnosis of acute parvovirus B19 infection is confirmed by detection of IgM antibodies. More than 90% of individuals have detectable IgM antibody by the time the rash appears. IgM antibody level peaks at 30 days and remains detectable for up to 3 months. 

IgG antibody appears during the first week of illness and remains detectable for life. The prevalence of parvovirus B19 IgG antibodies increases with age. Parvovirus IgG antibodies are detected in 2% to 9% of children under 5 years of age, 15% to 35% in children between 5 and 18 years of age, and 30% to 60% of adults. 

As the following table indicates, the presence of IgM indicates recent infection while IgG antibodies is suggestive of past exposure.

Epstein Barr virus infections and antinuclear antibodies may produce equivocal or positive IgM results. Patients who are immunosuppressed may not produce detectable Parvovirus antibodies. In these cases, parvovirus DNA can be detected by polymerase chain reaction (PCR). 

Antibody to parvovirus B19 is detected by a sandwich EIA for the detection of IgG or IgM class antibodies in serum or plasma. Reference value is negative for IgG and IgM.  

Specimen requirement is one SST tube of blood.

References

CDC Health Alert Network, Increase in Human Parvovirus B19 Activity in the United States, CDCHAN-00514, August 13, 2024.

Heegaard ED, Brown KE. Human parvovirus B19. Clin Microbiol Rev. 2002; 15(3):485–505.

Nordholm AC, Trier Møller F, Fischer Ravn S, et al. Epidemic of parvovirus B19 and disease severity in pregnant people, Denmark, January to March 2024. Euro Surveill. 2024; 29(24):2400299