دراسات عليا / كورس أول / Measles, Mumps and Rubella

Measles, Mumps and Rubella

Measles Pathogenesis and Clinical Features
Respiratory transmission of virus
Replication in nasopharynx and regional lymph nodes
Primary viremia 2-3 days after exposure
Secondary viremia 5-7 days after exposure with spread to tissues
Incubation period 10-12 days
Stepwise increase in fever to 103°F or higher
Cough, coryza, conjunctivitis
Koplik spots
2-4 days after prodrome, 14 days after exposure
Maculopapular, becomes confluent
Begins on face and head
Persists 5-6 days
Fades in order of appearance




Measles Complications
Condition
Diarrhea
Otitis media
Pneumonia
Encephalitis
Hospitalization
Death

Measles Epidemiology
Reservoir Human
Transmission Respiratory Airborne
Temporal pattern Peak in late winter–spring

Communicability 4 days before to 4 days after rash onset
Measles Vaccine
Composition Live virus
Efficacy 95% (range, 90%-98%)
Duration ofImmunity Lifelong
Schedule 2 doses
Should be administered with mumps and rubella as MMR, or with mumps, rubella and varicella as MMRV

1941 - 894,134 U.S. cases
1995 - 288 U.S. cases


Measles VaccineIndications for Revaccination
Vaccinated before the first birthday
Vaccinated with killed measles vaccine
Vaccinated prior to 1968 with an unknown type of vaccine
Vaccinated with IG in addition to a further attenuated strain or vaccine of unknown type
Mumps
Acute viral illness
Parotitis and orchitis described by Hippocrates in 5th century BC
Viral etiology described by Johnson and Goodpasture in 1934
Frequent cause of outbreaks among military personnel in prevaccine era
Mumps Virus
Paramyxovirus
RNA virus
One antigenic type
Rapidly inactivated by chemical agents, heat, and ultraviolet light
Mumps Pathogenesis
Respiratory transmission of virus
Replication in nasopharynx and regional lymph nodes
Viremia 12-25 days after exposure with spread to tissues
Multiple tissues infected during viremia
Mumps Clinical Features
Incubation period 14-18 days
Nonspecific prodrome of myalgia, malaise, headache, low-grade fever
Parotitis in 30%-40%
Up to 20% of infections asymptomatic

Mumps Complications
Mumps Epidemiology
Reservoir Human Asymptomatic infections may transmit
Transmission Respiratory drop nuclei
Temporal pattern Peak in late winter and spring
Communicability Three days before to four days after onset of active disease
Mumps Outbreak, 2006
Source of the initial cases unknown
Outbreak peaked in mid-April
Median age of persons reported with mumps was 22 years
Highest incidence was among young adults 18-24 years of age, many of whom were college students
Transmission of mumps virus occurred in many settings, including college dormitories and healthcare facilities
Factors Contributing To Mumps Outbreak, 2006
College campus environment
Lack of a 2-dose MMR college entry requirement or lack of enforcement of a requirement
Delayed recognition and diagnosis of mumps
Mumps vaccine failure
Vaccine might be less effective in preventing asymptomatic infection or atypical mumps than in preventing parotitis
Waning immunity

Mumps Vaccine
Composition Live virus (Jeryl Lynn strain)
Efficacy 95% (Range, 90%-97%)
Duration ofImmunity Lifelong
Schedule >1 Dose

Should be administered with measles and rubella (MMR) or with measles, rubella and varicella (MMRV)
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 (CRS) described by Gregg in 1941
Rubella Virus
Togavirus
RNA virus
One antigenic type
Rapidly inactivated by chemical agents, ultraviolet light, low pH, and heat
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
Maculopapular rash 14-17 days after exposure
Usually quite mild


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
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
Deafness
Cataracts
Heart defects
Microcephaly
Mental retardation
Bone alterations
Liver and spleen damage


Rubella Epidemiology
Reservoir Human
Transmission Respiratory Subclinical cases may transmit
Temporal pattern Peak in late winter and spring

Communicability 7 days before to 5-7 days
after rash onset  Infants with CRS may shed virus for a year or more

Rubella - United States, 1966-2005
Rubella Vaccine
Composition Live virus (RA 27/3 strain)
Efficacy 95% (Range, 90%-97%)
Duration ofImmunity Lifelong
Schedule At least 1 dose

Should be administered with measles and mumps as MMR or with measles, mumps and varicella as MMRV
Rubella Vaccine Arthropathy
Acute arthralgia in about 25% of vaccinated, susceptible adult women
Acute arthritis-like signs and symptoms occurs in about 10% of recipients
Rare reports of chronic or persistent symptoms
Population-based studies have not confirmed an association with rubella vaccine
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%
Measles Mumps Rubella Vaccine
12 -15 months is the recommended and minimum age (more effective at 15 months)
MMR given before 12 months should not be counted as a valid dose
2nd dose at 4-6 years
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
MMR Vaccine and Autism
Measles vaccine connection first suggested by British gastroenterologist
Diagnosis of autism often made in second year of life
Multiple studies have shown NO association

MMR VaccineContraindications and Precautions
Severe allergic reaction to vaccine component or following prior dose
Pregnancy
Immunosuppression
Moderate or severe acute illness
Recent blood product
Measles and Mumps Vaccines and Egg Allergy
Measles and mumps viruses grown in chick embryo fibroblast culture
Studies have demonstrated safety of MMR in egg allergic children
Vaccinate without testing
Measles Vaccine and HIV Infection
MMR recommended for persons with asymptomatic and mildly symptomatic HIV infection
NOT recommended for those with evidence of severe immuno- suppression

MMR Vaccines