Chapter 14: Rubella

Disease Description

Rubella is a viral illness caused by a single-stranded, positive sense RNA virus (family Matonaviridae, genus Rubivirus). Rubella is transmitted through direct, or droplet contact from nasopharyngeal secretions and has an average incubation period from exposure to rash onset of 17 days (range: 12–23 days)1. Persons with rubella are most infectious around the time of rash onset, but they can shed infectious virus from 7 days before to 7 days after rash onset.

Rubella's clinical presentation is marked by low-grade fever and mild, maculopapular rash, although 25%–50% of rubella infections are asymptomatic. The rubella rash occurs in 50%–80% of rubella-infected persons and is sometimes misdiagnosed as measles or scarlet fever. Children usually develop few or no constitutional symptoms, but adults may experience a prodrome of low-grade fever, headache, malaise, mild coryza, and conjunctivitis which can last 1–5 days. Additional symptoms include postauricular, occipital, and posterior cervical lymphadenopathy, which precedes the rash by 5–10 days, and arthralgia or arthritis, which may occur in up to 70% of adult women with rubella. Rare complications include thrombocytopenic purpura and encephalitis234.

When rubella infection occurs during pregnancy, especially during the first trimester, serious consequences can result. These include miscarriages, fetal deaths/stillbirths, premature births, and a constellation of birth defects known as congenital rubella syndrome (CRS). The most common congenital defects are cataracts, heart defects, and hearing impairment5. See Chapter 15, "Congenital Rubella Syndrome," for more details.

Rarely, following initial infection, rubella virus can establish persistent infections leading to various pathologies. These include skin and visceral granulomas (typically in persons with primary immunodeficiencies), Fuchs' uveitis, encephalitis, and chronic arthritis in adults67.

Background

Epidemiology of rubella in the United States

Rubella cases in the pre-elimination era

Before the availability of rubella vaccines in the United States, rubella was a common disease that occurred primarily among young children. Incidence was highest during the spring with epidemics every 6 to 9 years8. The last major epidemic in the United States occurred during 1964–1965, when there were an estimated 12.5 million rubella cases, resulting in 2,000 cases of encephalitis, 11,250 therapeutic or spontaneous abortions, 2,100 neonatal deaths, and 20,000 infants born with CRS9.

In 1969, live attenuated rubella vaccines were licensed in the United States. The goal of the rubella vaccination program was and continues to be to prevent congenital infections, including those that result in CRS10. Following vaccine licensure, the number of reported cases of rubella in the United States declined dramatically. During the 1990s, the median number of rubella cases reported annually was 232 (range: 128–1,412) and the incidence of rubella among children younger than 15 years of age decreased (from 0.63 per 100,000 population in 1990 to 0.06 in 1999), whereas the incidence among adults 15 to 44 years of age increased (from 0.13 per 100,000 in 1990 to 0.24 in 1999)11. During the 1990s and in 2000, rubella outbreaks occurred in congregate settings, especially among members of close-knit communities that traditionally refuse vaccination and among adults from countries without routine rubella vaccination programs1112. During 2001–2004, the median number of rubella cases reported annually was 14 (range: 7–23), and the incidence both among persons younger than 15 years of age and those 15 to 44 years of age was less than 1/10,000,000 population11.

In 2004, an independent panel of internationally recognized experts in public health, infectious diseases, and immunizations reviewed available data and unanimously agreed that rubella elimination* was achieved in the United States10.

*Elimination is defined as the absence of endemic rubella virus transmission for a continuous period of 12 months or more, in the presence of adequate surveillance (World Health Organization)

Rubella cases in the post-elimination era

During 2005–2022, 130 rubella cases were reported in the United States, with a median of six rubella cases reported annually (range: 2–18). Annual incidence has remained less than 1/10,000,000 population. A total of 56 (43%) cases were internationally imported; most importations resulted from travel to countries in the World Health Organization (WHO) Western Pacific and Southeast Asian Regions. Since 2004, only two rubella outbreaks** have been reported, each with three confirmed cases.

**National reporting: An outbreak is defined as a chain of transmission including 3 or more cases linked in time and space.

Global rubella

Despite substantial improvements in rubella elimination efforts, rubella continues to be endemic in many parts of the world. It is estimated that more than 32,000 infants worldwide are born annually with CRS13.

According to WHO, the number of countries that have incorporated rubella-containing vaccines (RCV) into their routine national immunization programs increased from 132 in 2012 to 175 (90% of 194 countries) in 202214. The proportion of infants receiving the first dose of RCV globally increased from 40% to 68% during 2012–2022 and reported rubella cases decreased from 93,816 in 2012 to 17,407 cases in 2022. Furthermore, the introduction of RCV averted an estimated 229,000 CRS cases globally during 2011–201913. Despite this progress, approximately 25 million infants each year do not have access to RCV14.

Five of the six WHO regions have established rubella and CRS regional elimination goals. The Eastern Mediterranean Region does not currently have an elimination target but has committed to achieving rubella elimination14. The Region of the Americas verified elimination of rubella in 201515; as of 2022, rubella elimination has been verified in 98 (51%) of 194 countries, and endemic transmission has not been reestablished in any country that has been verified to have achieved elimination14.

Maintenance of Elimination in the United States

Elimination of endemic rubella was documented in the United States in 2004 and verified in 2015. Sustained elimination was confirmed in 20241016. However, because of international travel and countries without routine rubella vaccination, imported cases of rubella remain likely. The key strategies for maintaining the elimination of rubella in the United States are:

• Continuing to maintain high vaccination rates among children;
• Ensuring that people with childbearing potential, particularly those born outside of the United States, are vaccinated; and
• Maintaining sensitive surveillance to detect both rubella and CRS.

Vaccination

Live attenuated rubella virus vaccine is incorporated into combination measles, mumps, and rubella (MMR) vaccine and combination measles, mumps, rubella, and varicella (MMRV) vaccine. Monovalent rubella vaccine and bivalent measles-rubella vaccine are not available in the United States. Two doses of MMR vaccine are recommended routinely for children, with the first dose at age 12 through 15 months and the second dose at ages four through six years (school entry)17. For specific information about the use of rubella vaccines, refer to The Pink Book, which provides general recommendations, including vaccine use and scheduling, immunization strategies for providers, vaccine content, adverse events and reactions, vaccine storage and handling, and contraindications and precautions.

Presumptive Evidence of Rubella Immunity

Acceptable presumptive evidence of rubella immunity includes at least one of the following17:

• Written documentation of adequate vaccination with at least one dose of live rubella virus-containing vaccine at age ≥12 months; or
• Laboratory evidence of rubella immunity (presence of anti-rubella IgG antibodies in serum); or
• Laboratory confirmation of rubella disease; or
• Birth before 1957.

Persons who do not meet the above criteria are considered susceptible and should receive one dose of MMR vaccine unless contraindicated.

Case Definition

Case definition for case classification

The following case definition for rubella was approved by the Council of State and Territorial Epidemiologists (CSTE) in 202418.

Clinical Evidence:

In the absence of a more likely alternative diagnosis:

• Acute onset of generalized maculopapular rash; and
• Fever (measured [greater than 99.0°F] or subjective); and
  • Arthralgia or arthritis, or
  • Cervical lymphadenopathy, or
  • Conjunctivitis

Probable:

A case that meets all the following criteria:

• Has clinical evidence; and
• Positive serologic test for rubella IgM antibody*,**,†; and
• Lacks presumptive evidence of rubella immunity^

Confirmed:

A case with or without clinical evidence and one of the following pieces of laboratory evidence:

• Detection of rubella virus (e.g., RT-PCR, culture, next generation sequencing [NGS])
• Significant rise, defined as seroconversion or at least a 4-fold rise in titer, observed in paired acute and convalescent serum rubella IgG antibody levels*

OR

A case with a positive serologic test for rubella IgM antibody*,**,† and one of the following pieces of evidence(s):

• Low avidity rubella IgG*; or
• Contact with a laboratory-confirmed†† rubella or congenital rubella case during the case's likely infectious period; or
• Clinical evidence and international travel in the 23 days prior to rash onset and lacks presumptive evidence of immunity^

OR

A case with clinical evidence and close contact (e.g., household contact) with a laboratory-confirmed†† rubella or congenital rubella case during the case's likely infectious period

OR

A case with or without clinical evidence who gave birth to an infant with confirmed congenital rubella^^

* In the absence of rubella vaccination during the previous 6–45 days.

** Acquired rubella was suspected, testing not conducted as part of routine screening (e.g., titers for employment documentation)

† When not superseded by more specific testing in a public health laboratory

†† "Laboratory-confirmed" case is a case that meets confirmatory laboratory evidence

^ Presumptive evidence of immunity is defined in Reference 17 (Table 3)17.

^^ When residency criteria are met for pregnant person (see CSTE PS 11-SI-04)

Epidemiologic classification of internationally imported and US-acquired cases

International importation: An internationally imported case is defined as a case in which rubella results from exposure to rubella virus outside the United States as evidenced by at least some of the exposure period (12–23 days before rash onset) occurring outside the United States, and the onset of rash within 23 days of entering the United States, and no known exposure to rubella in the United States during that time.

US-acquired case: A US-acquired case is defined as a case in which the patient had not been outside the United States during the 23 days before rash onset or was known to have been exposed to rubella within the United States.

US-acquired cases are subclassified into four mutually exclusive groups

Import-linked case: Any case in a chain of transmission that is epidemiologically linked to an internationally imported case.

Imported-virus case: A case for which an epidemiologic link to an internationally imported case was not identified, but for which viral genetic evidence indicates an imported rubella genotype, i.e., a genotype that is not occurring within the United States in a pattern indicative of endemic transmission.

An endemic genotype is the genotype of any rubella virus that occurs in an endemic chain of transmission (i.e., ≥12 months). Any genotype that is found repeatedly in US-acquired cases should be thoroughly investigated as a potential endemic genotype, especially if the cases are closely related in time or location.

Endemic case: A case for which epidemiologic or virologic evidence indicates an endemic chain of transmission. Endemic transmission is defined as a chain of rubella virus transmission continuous for ≥12 months within the United States.

Unknown source case: A case for which an epidemiologic or virologic link to importation or to endemic transmission within the United States cannot be established after a thorough investigation. These cases must be carefully assessed epidemiologically to assure that they do not represent a sustained US-acquired chain of transmission within the United States.

Note: Internationally imported, import-linked, and imported-virus cases are considered collectively to be import-associated cases.

States may also choose to classify cases as "out-of-state-imported" when imported from another state in the United States. For national reporting, however, cases will be classified as either internationally imported or US-acquired.

Laboratory Testing

Diagnosing rubella solely on clinical presentation is unreliable due to the common febrile rash symptoms; therefore, cases must be laboratory confirmed. To maximize the sensitivity and specificity of laboratory testing, healthcare providers should collect specimens for both molecular testing (e.g., reverse-transcription polymerase chain reaction (RT-PCR)) and serologic testing for suspected rubella cases.

Molecular Testing

RT-PCR

Clinical specimens for RT-PCR should be collected at the same time as samples taken for serologic testing. Detection of rubella RNA through RT-PCR testing is particularly helpful for case confirmation when serology results are inconclusive. Sensitivity is highest for RT-PCR within the first three days of rash onset, but viral RNA can be detected up to nine days following rash onset in 50% of patients19. Additionally, obtaining both respiratory and urine samples increases the likelihood of detecting viral material. Positive RT-PCR results confirm acute rubella infection unless there has been recent vaccination.

While RT-PCR is highly sensitive, a negative test result may not rule out rubella, especially when there is strong clinical or epidemiologic suspicion. The test can be affected by the timing of specimen collection and the quality and handling of clinical specimens, such that a poorly collected or poorly maintained specimen may yield a false-negative result. Therefore, a negative test should be interpreted in the clinical and epidemiologic context of the case to determine the likelihood of rubella infection.

Rubella Virus Sequencing (Genotyping)

Molecular epidemiologic surveillance provides critical data that can support a link (or lack thereof) of cases and outbreaks to each other or to source countries. Sequencing can be used to rule out cases related to vaccine reactions, track transmission pathways, and to document the absence of endemic circulation of rubella in the United States2021. All RT-PCR positive specimens for rubella should undergo sequencing at the CDC or one of the APHL Vaccine Preventable Disease Reference Centers.

Serologic Testing

Serologic testing can be performed to detect both rubella-specific IgG and IgM antibodies, along with IgG avidity testing for case classification. No single serologic laboratory test can confirm every true case of rubella with 100% certainty, and the likelihood of false-positive immunoglobulin M (IgM) results has increased in the U.S. as rubella incidence has decreased22. Therefore, results must be interpreted alongside other clinical, laboratory, and epidemiologic evidence. Serologic testing is not recommended for persons who have recently been vaccinated (6–45 days prior to blood collection) as neither IgM nor IgG antibody responses can distinguish rubella infection from the response to vaccination.

IgM

Following rubella virus infection in an unvaccinated individual, rubella-specific IgM antibodies appear and peak within 5 days of rash onset and may persist for up to 3 months2324. IgM antibodies may not be detectable on a serologic test during the first four days after rash onset; therefore, if serum that is collected 0–4 days after rash onset is negative, a second specimen should be collected ≥5 days after rash onset to confirm or rule out rubella. Detection of IgM may be variable in persons with pre-existing immunity who develop rubella25.

IgM testing should only be performed when acute rubella infection is suspected. False-positive IgM results due to cross-reactivity with other causes of viral exanthem, such as parvovirus, measles, and EBV, or the presence of rheumatoid factor are known to occur26. Frequently, IgM tests are inappropriately combined with IgG immunity tests during prenatal screening and school or employment titers, resulting in a higher undue suspicion of rubella in patients otherwise unlikely to have rubella. When no clinical or epidemiologic suspicion exists, false-positive IgM results create heavy investigative burdens and misclassification of rubella cases27.

IgG

Rubella-specific IgG antibodies appear after IgM, and can be detectable four days following rash onset, peaking over the next two weeks. Rubella IgG can persist for a person's lifetime and can be tested for evidence of immunity to rubella virus23. Immunity testing should not include IgM.

IgG Avidity

A single acute-phase serum sample can be tested for IgG avidity if the sample has detectable rubella-specific IgG. Low avidity IgG suggests a recent rubella infection (or recent vaccination) in cases without documented history of prior vaccination or infection, whereas a high avidity test result represents prior immunity, either from immunization or a previous infection. Avidity testing should especially be used to discriminate between distant and recent infections in pregnant persons with suspected rubella infection. Avidity testing is not used to investigate vaccine failures, which are very rare in the context of rubella.

Due to the lack of commercially available avidity tests in the U.S., use of the CDC lab-developed avidity test is typically limited to unusual cases, often reserved for highly suspicious sporadic cases or during an outbreak.

Rise of Rubella IgG Antibody Titers

Another definitive serologic indicator of recent rubella infection is seroconversion, denoted by a ≥4-fold increase in rubella-specific IgG antibody titers between acute and convalescent serum samples, as measured by a rubella IgG ELISA. Samples must be collected at least two weeks apart. This test requires quantitative measures of rubella-specific IgG antibodies. In cases of suspected rubella reinfection, which are typically asymptomatic, seroconversion identifies infection among case contacts as well.

Testing for seroconversion is rare. Prior approval for these tests should be obtained from the CDC Rubella Laboratory.

Focus reduction neutralization assay (FRNA)

Focus reduction neutralization assay (FRNA) can be used to measure levels of rubella neutralizing antibody in patient's sera, though data on protective threshold remains limited.

FRNA use is currently limited to research only and is not used for diagnostic purposes. Testing using FRNA requires specialized reagents and is both labor- and time-intensive, curbing its widespread use.

Specimen collection

Specimen collection and shipping are important steps in obtaining laboratory diagnosis or disease confirmation for vaccine preventable diseases. Guidelines have been published for specimen collection and handling for viral and other microbiologic agents. Specific instructions for specimen collection and shipping for rubella specimens may be obtained from the CDC Rubella Laboratory website or by contacting the CDC Viral Vaccine Preventable Diseases Branch at 404-639-6403. Specimens for virus isolation and sequencing should be sent to CDC as directed by the State Health Department.

General information is also available on using CDC laboratories as support for reference and disease surveillance; this includes:

• A central website for requesting lab testing;
• The form required for submitting specimens to CDC (See Form # CDC 0.5034);
• Information on general requirements for shipment of etiologic agents (see Appendix 24) —although written to guide specimen submission to CDC, this information may be applicable to submission of specimens to other laboratories; and
• The CDC Infectious Diseases Laboratories Test Directory, which not only contains a list of orderable tests for that institution, but also detailed information such as appropriate specimen types, collection methods, specimen volume, and points of contact.

The APHL/CDC Vaccine Preventable Disease Reference Centers perform real-time RT-PCR and genotyping for rubella.

For additional information on laboratory testing for rubella and for specific information on specimen collection and shipment, see Chapter 22, "Laboratory Support for the Surveillance of Vaccine-Preventable Diseases."

Reporting and Case Notification

Case reporting within a jurisdiction

Each state and territory has regulations or laws governing the reporting of diseases and conditions of public health importance28. Rubella is nationally notifiable and should be reported in a timely manner to state or local health departments; the specific requirements may differ by state28.

Rapid case identification, investigation, and reporting is important to avoid exposure of susceptible pregnant persons and so that control measures can be initiated to prevent spread of the disease. The Rubella Surveillance Worksheet is included as Appendix 16, to serve as a guide for data collection during investigation of reported cases.

Case notification to CDC

Since continuous endemic rubella transmission has been eliminated, rubella is an immediately notifiable disease. Rubella cases should be reported promptly (within 24 hours28) by the state health department to the CDC directly by e-mail ([email protected]). Notification of confirmed cases using the event code 10200 should then be electronically reported by the state health department to the National Notifiable Diseases Surveillance System (NNDSS) with the next regularly scheduled electronic transmission. Case notification should not be delayed due to incomplete information. Data previously submitted to NNDSS should be updated with any new available information following completion of case investigations.

Information to collect

The following data elements are epidemiologically important and should be collected during case investigation. Additional information may be collected at the direction of the state or local health department.

Demographic information

• Name
• Address
• Date of Birth
• Age
• Sex
• Race
• Ethnicity
• Country of birth
• Residency (e.g., Does the case-patient reside in the United States or is a foreign visitor?)

Reporting source

• State
• County
• Date first reported to a health department

Clinical Presentation

• Date of illness onset
• Date of rash onset
• Rash duration
• Date of fever onset
• Prodromal symptoms (i.e., fever [note highest temperature], arthralgia, arthritis, lymphadenopathy, conjunctivitis)
• Complications (including encephalitis, thrombocytopenia, other)
• Pregnancy status (if applicable)
  • Number of weeks gestation at onset of illness
  • Number and dates of previous pregnancies and location (e.g., state or country) of these pregnancies
  • Pregnancy outcome or complications, when available (e.g., normal infant birth, premature birth, termination, CRS)
  • Reported history of rubella disease, date of serologic immunity, or both

Outcomes

• If hospitalized,
  
  • Date of hospitalization
  • Reason for hospitalization (if known)
  • Duration of hospitalization
• If deceased,
  
  • Date of death
  • Results of postmortem examination
  • Death certificate diagnoses

Laboratory

• Molecular tests
  • Specimen source (i.e., throat/NP swab, urine)
  • Test type (RT-PCR, genotyping, cell culture, or other molecular tests)
  • Date of specimen collection
  • Test results
• Serological tests
  • Test type (IgM, IgG, avidity, PRN)
  • Date of specimen collection
  • Test results

Vaccination status

• Number of doses of rubella-containing vaccine received
• Type(s) of vaccine received (rubella, MMR, MMRV)
• Date(s) of dose(s) of rubella-containing vaccinations received
• Country of vaccination
• If not vaccinated, reason

Epidemiological

• Transmission setting (e.g., infection acquired at home, healthcare setting, travel, event)
• Source of infection (e.g., relationship to case, contact with probable or confirmed case, contact with immigrants or travelers, or international travel)
• Import status (international import or US-acquired case, see section “Case Definition”)
• Travel history in the 23 days prior to symptom onset, including destinations and flight or maritime information
• Date of return to United States
• Relationship to outbreak (Is case part of an outbreak or is it sporadic?)
• Number of contacts

Importance of Rubella Surveillance

Surveillance data are needed to identify and control rubella virus introductions to prevent congenital rubella infections and consequent CRS. Additionally, timely reporting and investigations are crucial to monitor the maintenance of disease elimination.

Promote awareness of rubella and CRS in the United States among health care providers

Although only 130 cases of rubella and 15 cases of CRS were reported between 2005 and 2022, it is likely that not all cases were identified. Symptomatic cases may be incorrectly classified, and asymptomatic cases may not present to healthcare facilities.

Although global vaccination against rubella virus has increased in recent years, many rubella infections and CRS births occur annually, primarily in nations that do not require rubella in their national vaccination schedules29. Thus, many persons born outside the United States or who received childhood immunizations in other countries may have never received a rubella-containing vaccine. Healthcare providers should have heightened suspicion for rubella infection and CRS births in persons from countries without a history of routine rubella vaccination programs or those with recently implemented programs.

Monitoring surveillance indicators

Regular monitoring of surveillance indicators, including time intervals between diagnosis to case report and completeness of reporting, may identify specific areas of the surveillance and reporting system that need improvement. An important indicator of the adequacy of the rubella surveillance system is the detection of importations. In the absence of rubella endemic transmission, imported cases or cases linked to importations should be identified. For more information on surveillance indicators, see Chapter 18, "Surveillance Indicators."

The following indicators should be monitored:

• The proportion of confirmed cases reported to the NNDSS with complete information
• The median interval between rash onset and notification of a public health authority, for confirmed cases
• The proportion of confirmed cases that are laboratory confirmed
• The proportion of cases that have an imported source
• The proportion of cases for which at least one clinical specimen for virus isolation was collected

Case and Contact Investigations

All reports of suspected rubella cases should be investigated immediately.

In the rubella post-elimination era, a single reported case is considered a public health priority that requires rapid and appropriate public health response. Rubella is an infectious disease for which up to 50% of cases are asymptomatic, and investigation of an apparently isolated case could reveal additional cases. Therefore, health agencies should consider a single case of rubella as a potential outbreak. The Rubella Surveillance Worksheet may be used as a guideline in conducting a case investigation. Case investigation and identification of contacts should be conducted for all suspected cases of rubella.

The goals of rubella case investigation are to identify rubella infections, particularly infection in pregnant persons, and to prevent exposure of susceptible pregnant persons, thereby preventing cases of CRS. It is essential that exposed pregnant persons be identified, evaluated, and counseled (see section on laboratory evaluation of exposed pregnant persons).

Confirm a diagnosis of rubella

Since clinical signs of rubella are also common to many other viral diseases and rubella cases may present asymptomatically, clinical diagnosis alone is unreliable. Known contact with a confirmed rubella or congenital rubella case or recent travel to a geographic area with known rubella transmission should increase suspicion of acquired rubella infection.

If rubella is suspected, specimens should be collected for both molecular and serologic testing at the time of the initial investigation. See Appendix 15 for specimen collection procedures. It is important to consider rubella in the differential diagnoses of patients under evaluation for other febrile rash illnesses, including measles, parvovirus, dengue, Kawasaki disease, and scarlet fever. Additionally, when evaluating patients with suspected measles who have negative molecular and serologic tests for acute measles infection, additional testing for rubella can be considered.

Patients who are both epidemiologically linked to a laboratory-confirmed case and were vaccinated within 23 days of a rubella-like illness should have specimens collected for molecular testing to determine if the rash is attributable to wild-type virus or vaccine virus. Investigation should not be delayed while laboratory test results are pending.

Identify the source of infection

Efforts should be made to identify the source of infection for every confirmed case of rubella. Case-patients or their caregivers should be asked about contact with other known cases. Since many rubella cases are asymptomatic, identification of a source will not always be possible. When no history of contact with a known case can be elicited, opportunities for exposure to unidentified cases during the incubation period (i.e., 12–23 days prior to rash onset) in populations at high risk should be sought (e.g., in schools, during air travel, through other contact with recent travelers or foreign visitors, while visiting tourist locations [casinos, resorts, theme parks], in health care settings, or in churches). Unless a history of exposure to a known case is confirmed, case-patients or their caregivers should be closely queried about all these possibilities.

Identify exposed contacts

Any direct contact with a patient with rubella during the infectious period (7 days before to 7 days after rash onset) is defined as an exposure. High priority groups to inquire about include 1) household contacts, 2) close contacts other than household (e.g., persons who shared the same room or airspace in various settings), and 3) schools/childcare centers, colleges, or other close settings where a defined number of persons have congregated. All contacts should be evaluated for evidence of immunity.

Obtain accurate and complete immunization histories

Rubella case investigations should include complete immunization histories that document all doses of RCV. Acceptable proof of vaccination is documented administration of live rubella virus-containing vaccine. Written records (including personal copies of immunization records) or electronic records (including immunization information system and electronic medical records) with dates of vaccine administration are the only acceptable evidence of vaccination; self-reported history of vaccination is not valid. The vaccination status of persons for whom vaccination status cannot be verified should be classified as unknown.

Postexposure vaccination and use of immune globulin

Postexposure administration of MMR vaccine is not recommended as it not been shown to prevent rubella illness1. However, MMR should be offered to susceptible, nonpregnant persons at any interval to offer protection against future exposures. Postexposure administration of immune globulin is not recommended for routine use in pregnant persons as it has not been demonstrated to prevent CRS1.

Conduct laboratory evaluation of exposed pregnant persons

Every effort should be made to identify all pregnant persons who might have been exposed to a suspected rubella case. All people with childbearing potential who are contacts of a rubella case should have their pregnancy status determined. Asymptomatic rubella infections can result in CRS; therefore, exposed pregnant persons should be monitored throughout their pregnancy, although risk of vertical transmission of CRS is highest during the first trimester. See Chapter 15, "Congenital Rubella Syndrome," for more details.

Regardless of symptom history, a blood specimen should be collected as soon as possible, tested for presence of rubella IgG and IgM antibody, and stored for possible retesting. See Chapter 22, "Laboratory Support for Surveillance of Vaccine-Preventable Diseases" for information on serologic evaluation of pregnant persons exposed to rubella.

Report the pregnancy outcome for persons diagnosed with rubella during pregnancy

All pregnancy outcomes among persons infected with rubella during pregnancy should be documented and reported to CDC (e.g., normal infant, termination, CRS), and appropriate testing should be performed on the infant after birth. See Chapter 15 "Congenital Rubella Syndrome," for more details.

Implement control measures

Control measures should be implemented as soon one case of rubella is confirmed in a community. In settings where pregnant persons may be exposed, control measures should begin as soon as rubella is suspected and should not be postponed until laboratory confirmation. Patients with rubella should be isolated for seven days after rash onset. If medical care is sought during the infectious period, droplet precautions should be taken.

All persons at risk who cannot readily provide acceptable evidence of rubella immunity should be considered susceptible and should be vaccinated.

Exclusion of contacts without presumptive evidence of immunity

If a pregnant person lacks laboratory evidence of rubella immunity, precautions should be taken to prevent any type of exposure to persons infected with rubella; these precautions may include ensuring rubella immunity of household contacts and excluding susceptible pregnant persons from settings where rubella virus has been identified.

In day care centers, schools and other educational institutions, exclusion of persons without acceptable evidence of rubella immunity may limit disease transmission and may help to rapidly raise the vaccination level in the target population. All persons who have been exempted from rubella vaccination for medical, religious, or other reasons also should be excluded from attendance. Exclusion should continue until 23 days after the onset of rash of the last reported case-patient in the outbreak setting. Unvaccinated persons who receive MMR vaccine as part of the outbreak control may be immediately readmitted to school provided all persons without documentation of immunity have been excluded.

In healthcare settings, exposed healthcare personnel without adequate presumptive evidence of immunity should be excluded from duty beginning 7 days after exposure to rubella and continuing through either 23 days after last exposure or 7 days after rash appears. Exposed healthcare personnel who are vaccinated as part of control measures should be excluded from direct patient care for 23 days after the last exposure to rubella because effectiveness of postexposure vaccination in preventing rubella infection has not been shown30. In addition, because birth before 1957 does not guarantee rubella immunity, during outbreaks in healthcare settings, healthcare facilities should recommend one dose of MMR vaccine for unvaccinated personnel born before 1957 who lack laboratory evidence of rubella immunity or laboratory confirmation of infection or disease31.

Conduct enhanced surveillance

Active surveillance for rubella should be maintained for at least two incubation periods (46 days) following rash onset of the last case. Two incubation periods allow for the identification of transmission from a subclinical case. In addition, surveillance for CRS should be implemented when confirmed or probable rubella cases are documented in a setting where pregnant persons might have been exposed.

Due to the elimination of rubella, all identified rubella cases in the United States should be import-associated, and thus, surveillance should have an increased focus on identifying the source of importation. Additional guidelines for enhancing surveillance are given in Chapter 19, "Enhancing Surveillance."

Resources

• Webcast related to this manual
• Rubella vaccination

Acknowledgements

Prior versions of this chapter were authored by Susan Redd, Emily Abernathy, and Joseph Icenogle.

Authors and Suggested Citation

Adria Mathis, MSPH; Kelley Raines, MPH; Nicole Wiley, MPH; Thomas D. Filardo, MD; Min-hsin Chen, PhD; Ludmila Perelygina, PhD; David Sugerman, MD; Tatiana Lanzieri, MD

Suggested citation:

Given the variations in the timing for when chapter updates are made, a Manual edition number is no longer used. Therefore, it is recommended that the date at the top right of the web page be used in references/citations.

Content source:
National Center for Immunization and Respiratory Diseases