Rubella and Rubella Vaccine

Epidemiology and Prevention of Vaccine-Preventable Diseases

National Immunization ProgramCenters for Disease Control and Prevention

Dr Esteghamati EPI Manager

Rubella

• From Latin meaning "little red"

• Discovered in 18th century - thought to be variant of measles

• First described as distinct clinical entity in German literature

• Congenital rubella syndrome described by Gregg in 1941

Rubella Virus

• Togavirus

• RNA virus

• One antigenic type

• Rapidly inactivated by chemical agents, low pH, heat and ultraviolet light

Rubella Pathogenesis

• Respiratory transmission of virus

• Replication in nasopharynx and regional lymph nodes

• Viremia 5-7 days after exposure with spread to tissues

• Placenta and fetus infected during viremia

Rubella Clinical Features

• Incubation period 14 days (range 12-23 days)

• Prodrome of low grade fever

• Lymphadenopathy in second week

• Maculopapular rash 14-17 days after exposure

Rubella Complications

Arthralgia or arthritischildrenadult female

Thrombocytopenic purpuraEncephalitisNeuritisOrchitis

rareup to 70%

1/3000 cases

1/6,000 casesrarerare

Congenital Rubella Syndrome

• Infection may affect all organs

• May lead to fetal death or premature delivery

• Severity of damage to fetus depends on gestational age

• Up to 85% of infants affected if infected during first trimester

Congenital Rubella Syndrome (CRS)

Congenital Rubella Syndrome

• Deafness

• Cataracts

• Heart defects

• Microcephaly

• Mental retardation

• Bone alterations

• Liver and spleen damage

CRS case definitions (1)

Suspected CRS: A child <1 year with

• maternal history of rubella in pregnancy

and/or

• heart disease, or deafness, or eye signs:

white pupil (cataract); diminished vision; pendular eye movement (nystagmus); squint; smaller eye ball (micropthalmos);larger eye ball (congenital glaucoma)

CRS case definitions (2)

Clinically confirmed CRS: A child <1 year with two complications in group (a) or

one from (a) and one from (b)

(a) cataract(s), congenital glaucoma, congenital heart disease, loss of hearing, pigmentary retinopathy

(b) purpura, splenomegaly, microcephaly, mental retardation, meningoencephalitis, radiolucent bone disease, jaundice with onset within 24 hours after birth.

CRS case definitions (3)

Laboratory-confirmed CRS:

An infant with a positive blood test for rubella-specific IgM and clinically-confirmed CRS.

Congenital rubella infection (CRI):

An infant with a positive blood test for rubella-specific IgM who does not have clinically-confirmed CRS.

TOP PRIORITY: Use rubella vaccine to prevent CRS

• To prevent CRS iTo prevent CRS introduce rubella vaccine for ntroduce rubella vaccine for women of childbearing agewomen of childbearing age

• Define age of target group

– consider local fertility rates

• Where to offer vaccine

– postpartum and family planning

– mass campaigns (Cuba, Malaysia)

Epidemic Rubella – United States, 1964-1965

• 12.5 million rubella cases

• 2,000 encephalitis cases

• 11,250 abortions (surgical/spontaneous)

• 2,100 neonatal deaths

• 20,000 CRS cases–Deaf - 11,600–Blind - 3,580–Mentally retarded - 1,800

Rubella Laboratory Diagnosis

• Isolation of rubella virus from clinical specimen (e.g., nasopharynx, urine)

• Significant rise in rubella IgG by any standard serologic assay (e.g., enzyme immunoassay)

• Positive serologic test for rubella IgM antibody

Rubella Epidemiology

• Reservoir Human

• Transmission RespiratorySubclinical cases may

transmit

• Temporal pattern Peak in late winter and spring

• Communicability 7 days before to 5-7 daysafter rash onsetInfants with CRS may shedvirus for a year or more

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Rubella CRS

Rubella - United States, 1966-2002

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Rubella - United States, 1980-2002

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Age Distribution of Reported Cases

<5 yrs

15-39 yrs

>40 yrs

5-14 yrs

Rubella and CRS in the United States

• Most reported rubella in the U.S. since the mid-1990s has occurred among foreign-born Hispanic adults

• Rubella outbreaks have occurred in workplaces where most employees are foreign-born

• Majority of CRS since 1997 occurred in children of unvaccinated women born to Hispanic women, most born in Latin America

Rubella Case Definition

• Acute onset of generalized maculopapular rash, and

• Temperature of >37.2 C (>99 F), if measured, and

• Arthralgia or arthritis, or lymph-adenopathy, or conjunctivitis

Rubella Outbreak Control Guidelines

• Laboratory diagnosis of rubella and CRS

• Step-by-step guidelines on evaluation and management of outbreak

• Rubella prevention and control among women of childbearing age

• Rubella and CRS surveillanceMMWR 2001;50(RR-12)

VaccineGMK-3:RK53

HPV-77:DK12

HPV-77:DE5

RA 27/3*

Trade Name Cendevax

Rubelogen

Meruvax

Meruvax II

Licensure1969

1969

1969

1979

*Only vaccine currently licensed in U.S.

Rubella Vaccine

Rubella Vaccine

• Composition Live virus (RA 27/3 strain)

• Efficacy 95% (Range, 90%-97%)

• Duration ofImmunity Lifelong

• Schedule >1 Dose

• Should be administered with measles and mumps as MMR

Rubella Vaccine (MMR) Indications

• All infants >12 months of age

• Susceptible adolescents and adults without documented evidence of rubella immunity

• Emphasis on non-pregnant women of childbearing age, particularly those born outside the U.S.

Rubella Immunity

• Documentation of one dose of rubella-containing vaccine on or after the first birthday

• Serologic evidence of immunity

• Birth before 1957 (except women of childbearing age)

• Birth before 1957 is not acceptable evidence of rubella immunity for women who might become pregnant

• Only serology or documented vaccination should be accepted

Rubella Immunity

MMR Adverse Reactions

• Fever 5%-15%

• Rash 5%

• Joint symptoms 25%

• Thrombocytopenia <1/30,000 doses

• Parotitis rare

• Deafness rare

• Encephalopathy <1/1,000,000 doses

Rubella Vaccine Arthropathy

• Acute joint symptoms in about 25% of susceptable adult women

• Frank arthritis occurs in about 10%

• Rare reports of chronic or persistent symptoms

• Population-based studies have not confirmed association

• Severe allergic reaction to vaccine

component or following prior dose

• Pregnancy

• Immunosuppression

• Moderate or severe acute illness

• Recent blood product

MMR VaccineContraindications and Precautions

Vaccination of Women of Childbearing Age

• Ask if pregnant or likely to become so in next 4 weeks

• Exclude those who say "yes"

• For others– Explain theoretical risks– Vaccinate

Vaccination in Pregnancy Study 1971-1989

• 321 women vaccinated

• 324 live births

• No observed CRS

• 95% confidence limits 0%-1.2%

Rubella VaccineRecommendations for Increasing Coverage

• Continued routine vaccination of children at age >12 months with vaccination required for school entry

• Screen and vaccinate susceptible persons– healthcare workers– college entry– prenatal with postpartum vaccination– other healthcare visits– workplace