Rubella
Pregnant women exposed to rubella, 7-10 days after rash
| Not immune | Early Acute phase | Acute phase or primary infection | Chronic phase or reinfection | ||
|---|---|---|---|---|---|
| Description | No symptoms | Typical rash and flu-like symptoms or asymptomatic | Asymptomatic | ||
| Rubella IgM | - | + | + | + | - |
| Rubella IgG | - | - | + | + | + |
| Rubella IgG Avidity and/or Immunoblot* | n.a. | Low | Low | High | n.a./High |
* performed only in specialized labs.
n.a. not applicable
Adapted from:
- Iyanger N, et al. Guidance on the investigation, diagnosis and management of viral rash illness, or exposure to viral rash illness, in pregnancy. Public Health England publications gateway number GW-231. [Internet; updated 2023 Nov 28; cited 2024 Mar 5]. Available from: https://www.gov.uk/government/publications/viral-rash-in-pregnancy.
- U.S. Department of Health and Human Services, Centers for Disease Control and Prevention (CDC). Manual for the Surveillance of Vaccine-Preventable Diseases. Chapter 14: Rubella. Surveillance Manual. [Internet; updated 2020 Mar 6; cited 2024 Mar 5]. Available from: https://www.cdc.gov/vaccines/pubs/surv-manual/chpt14-rubella.html.
- Lambert N, et al. Rubella. Lancet. 2015;385:2297-2307.
- Bouthry E, et al. Rubella and pregnancy: diagnosis, management and outcomes. Prenatal Diagnosis. 2014;34:1246–1253.
- Abernathy E, et al. Confirmation of rubella within 4 days of rash onset: comparison of rubella virus RNA detection in oral fluid with immunoglobulin M detection in serum or oral fluid. J Clin Microbiol. 2009;47:182-188.
- Vauloup-Fellous C and Grangeot-Keros L. Humoral immune response after primary rubella virus infection and after vaccination. Clin Vaccine Immunol. 2007;14:644-647.
- Banatvala JE and Brown DWG. Rubella. Lancet. 2004;363:1127-1137.
a) for use on the cobas® e 411 analyzer and the cobas® e 601 / 602 modules
b) for use on the cobas® e 402 and cobas® e 801 analytical units
| Rubella IgM | Rubella IgG | Interpretation |
|---|---|---|
| - | - | Susceptible / No current or previous rubella infection; repeat IgM and IgG testing 2 – 3 weeks later; before pregnancy or post-partum vaccination is recommended. |
| - | + | Immune; no further testing required. The presence of antibodies at any level is sufficient to confirm immunity6. |
| + | - | Acute or recent rubella infection or false positive/unspecific IgM. Best period for testing is in a serum collected within the first few days after rash onset. Test for other causes, e.g. rheumatoid factor, EBV, CMV, Parvovirus B19. Test a second sample 5 – 10 days later, if available, and perform IgG avidity. A significant rise of the rubella IgG titer from a first to a second sample supports the diagnosis of acute rubella infection. |
| + | + |
* except infants
Adapted from:
- U.S. Department of Health and Human Services, Centers for Disease Control and Prevention (CDC). Manual for the Surveillance of Vaccine-Preventable Diseases. Chapter 14: Rubella. Surveillance Manual. [Internet; updated 2020 Mar 6; cited 2024 Mar 5]. Available from: https://www.cdc.gov/vaccines/pubs/surv-manual/chpt14-rubella.html.
- Picone O, et al. Determination of rubella virus-specific humoral and cell-mediated immunity in pregnant women with negative or equivocal rubella-specific IgG in routine screening. J Clin Virol. 2019;112:27–33.
- Picone O and Grangeot-Keros L. Rubéole et grossesse. EMC-Gynécologie-Obstétrique. 2005;2:343-353.
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Perform Rubella IgM and IgG tests in parallel
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Perform IgG Avidity test
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Repeat IgM and IgG tests in parallel
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Repeat IgM and IgG tests in parallel
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Summary
Immunity to rubella.
No further testing required.
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Summary
Acute infection
Symptomatic treatment
Assessment of fetal infection with PCR in chorionic villous and amniotic fluid samples.
Discuss options for pregnancy outcome.
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Summary
Acute or recent infection excluded.
Likely false IgM positive or persistent IgM.
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Summary
Acute infection
Symptomatic treatment.
Assessment of fetal infection with PCR in chorionic villous and amniotic fluid samples.
Discuss options for pregnancy outcome.
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Summary
Acute infection suspected due to IgG seroconversion or reinfection in case of history of vaccination.
Repeat testing and perform IgG avidity test. High IgG avidity confirms a reinfection, while low IgG avidity indicates a primary infection.
Make sure follow-up testing is always done with assays from the same manufacturer.
Symptomatic treatment.
Assessment of fetal infection with PCR in chorionic villous and amniotic fluid samples.
Discuss options for pregnancy outcome.
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Summary
Acute infection suspected or false positive IgM.
Acute infection is highly suspected if IgM reactivity is confirmed.
If IgM reactivity is not confirmed, the result is considered to be false positive.
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Summary
No acute infection, susceptible to infection.
Advice, monitoring, and vaccination before pregnancy or after delivery.
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Summary
Acute infection.
Symptomatic treatment.
Assessment of fetal infection with PCR in chorionic villous and amniotic fluid samples.
Discuss options for pregnancy outcome.
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- Step 3
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Summary
Acute infection suspected or false positive IgM.
Repeat IgM testing and confirm with immunoblot if possible.
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Summary
Acute infection suspected due to IgG seroconversion or reinfection in case of history of vaccination.
Make sure follow-up testing is always done with assays from the same manufacturer.
IgG test = ...
IgG test = negative
Repeat IgM and IgG tests 3 to 4 weeks from suspected exposure.
IgG test = positive
IgG test = negative
Acute or recent rubella infection or false positive/unspecific IgM.
Test a second sample 5 – 10 days later, if available, and perform IgG avidity in case of positive IgG.
IgG test = positive
Best period for testing is within the first few days after rash onset. Test for other possible causes like rheumatoid factor, EBV, CMV, or Parvovirus B19 infection.
Perform IgG Avidity test 5 –10 days later on 2nd sample. Also, repeat IgM and IgG tests with 2nd sample to confirm 1st result.
Acute or recent infection is excluded. Likely a persistent or false positive IgM.
IgG test = ...
IgG test = negative
Susceptible to infection.
Repeat IgM and IgG tests in parallel.
IgG test = positive
Acute infection suspected due to IgG seroconversion or reinfection in case of history of vaccination.
Make sure follow-up testing is always done with assays from the same manufacturer.
IgG test = negative
Acute infection suspected or false positive IgM.
Repeat IgM testing and confirm with immunoblot if possible.
IgG test = positive
IgG test = ...
IgG test = negative
No acute infection, susceptible to infection.
Vaccination is recommended.
IgG test = positive
Acute infection suspected .
IgG test = negative
Acute infection suspected or false positive IgM.
IgG test = positive