Measles and measles vaccine

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Epidemiology of Mumps and Multistate Mumps
Outbreak United States 2006
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Outline

• Clinical Characteristics
• Epidemiology of mumps
• Multistate Outbreak, 2006
• Vaccine recommendations
• Challenges

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Mumps

• Acute viral illness
• Parotitis and orchitis described by Hippocrates
  in 5th century B.C.
• Viral etiology described by Johnson and
  Goodpasture in 1934
• Frequent cause of outbreaks among military
  personnel in prevaccine era

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Mumps Virus

• Paramyxovirus
• RNA virus
• One antigenic type
• Rapidly inactivated by chemical agents, heat and
  ultraviolet light

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Mumps Clinical Features

• Incubation period 14 - 18 days
• Nonspecific prodrome of low-grade fever,
  headache, malaise, myalgias
• Parotitis in 30 - 40
• Up to 20 of infections asymptomatic
• May present as lower respiratory illness,
  particularly in preschool-aged children

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Mumps Complications
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Mumps Epidemiology

• Reservoir Human
• Transmission Respiratory drop nuclei
• Subclinical infections may transmit
• Temporal pattern Peak in late winter and spring
• Communicability Three days before to four
• days after onset of active
• disease

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• Mumps United States, 1968- 2005

2005 provisional data
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• Mumps United States, 1980- 2005

2-dose schedule
2005 provisional data
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U.S. Mumps Cases

• 2005 265 cases
• 2004 258 cases
• 2002 270 cases
• 1996 751 cases
• 1993 1,692 cases
• 2010 Health Objective is to eliminate indigenous
  mumps by 2010

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Mumps Outbreak NY State, 2005
MMWR Feb 24, 2006
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• Mumps Outbreak United States 2006

Total reported cases 4,602
4
193
1
650
1,921
85
349
501
3
134
782
1
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In PA, 14 of the 85 cases are considered
outbreak-associated.

• Provisional Number of Cases by State as of June
  20, 2006

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Week of Onset for Mumps Cases in the Eight the
Outbreak States, NNDSS (Provisional), 1 January
20 June, 2006 (n3860)
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Incidence of Mumps by Week of Onset, NNDSS
(Provisional), 1 January 20 June 2006
(n3860)1,2,3
Nebraska
Iowa
Pennsylvania
Missouri
Illinois
South Dakota
Kansas
Wisconsin
1 Per 100,000 2 Incidence scale differs by
state 3Through NNDSS week 24
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Demographic Summary of Reported Mumps Cases,
NNDSS (Provisional), January 1-June 20, 2006
(n3860)
1940 (50) 1920 (50) 2525 (65) Median 22
years Rangelt1-96
Reported from -- Iowa -- Other 7 OB
states Female Age
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Incidence of Mumps/100,000, 8 Outbreak-Associated
States, NNDSS (Provisional), 1 January 20 June
2006

• Iowa 65.3
• Kansas 28.0
• South Dakota 24.1
• Nebraska 17.1
• Wisconsin 4.9
• Missouri 3.1
• Illinois 1.1
• Pennsylvania 0.7

States with delayed reporting through NNDSS,
rates likely to increase
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Incidence of Mumps by Age Group in the Eight
Outbreak States, NNDSS (Provisional), 1 January
20 June 2006 (n3860)
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Provisional Incidence of Mumps Cases by Age
Group, NNDSS 1 January 20 June 2006 (n3860)
Iowa
Other seven states IL, KS, MO, NE, PA, SD, WI
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Multistate Mumps Outbreak 2006

• College students especially in Iowa
• Cases in health care workers
• Few outbreaks reported in schools or child care
  centers
• Transmission remained fairly focal
• Little or no spread to vaccine refuser
  populations and very few cases in infants
• Vaccination status cases poorly reported through
  NNDSS to date
• (Iowa June 17th 2006)
• 7 unvaccinated
• 14 1 dose
• 50 2 doses
• 30 unknown vaccination status (majority adults)

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Multistate Mumps Outbreak 2006

• Mumps G genotype (20 specimens from 9 states) -
  source unknown

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Clinical Summary of Reported Mumps Cases, NNDSS
(Provisional), January 1-June 20, 2006 (n3860)
Number () 2215 (80.8) 10 (0.4) 5 (0.2) 59
(4.4) 6 (0.2) 43 (1.6) 0
Clinical Feature (n)1 Parotitis (2741) Meningitis
(2542) Encephalitis (2530) Orchitis
(1333)2 Deafness (2536) Hospitalization
(2745) Death (2745)
1 Number with Yes or No in data field
included. Cases with Unknown or missing data
excluded. 2 Data collected among males only.
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Hospitalizations

• Two data sources for hospitalization (1 January
  20 June 2006)
• NNDSS 43 hospitalizations
• Biweekly Report 66 hospitalizations
• Data source for reason for hospitalization
  Biweekly Report only
• 11 of 66 hospitalizations likely NOT to be
  mumps-related
• Hospitalized for another reason (e.g., colitis,
  pneumonia) and found to have mumps
• Reason for hospitalization (n55)1

1 Not mutually exclusive (ie., may have gt1 reason)
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Epidemiological and Laboratory InvestigationsPrel
iminary Data

• Attack rates in 2 highly affected college
  campuses Iowa
• 2.0 (97 college students 2 vaccine doses)
• 3.8 (77 college students 2 vaccine doses)
• Vaccine failure rate (college room mate contact
  study Iowa)
• 2 dose recipients 8

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Mumps Vaccine

• Composition Live virus (Jeryl Lynn strain)
• Efficacy 95 (Range, 90 - 97)
• Duration ofImmunity Lifelong
• Schedule 2 Doses (as MMR)
• Should be administered with measles and rubella
  (MMR)

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Mumps Vaccine EfficacyClinical Trials
Study Population Vaccine Strain Year Vaccine Efficacy 95 CI
Philadelphia Jeryl Lynn 1965-67 95 88-98
North Carolina Jeryl Lynn 1966-67 96 88-99
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Mumps Vaccine EffectivenessOutbreak Studies
Study Population Vaccine Strain Year Vaccine Effectiveness 95 CI
New York Jeryl Lynn 1973 79 53-91
Canada Jeryl Lynn 1977 75 49-87
Ohio Jeryl Lynn 1981 81 88-98
Ohio Jeryl Lynn 1982 85 39-94
New Jersey Jeryl Lynn 1983 91 77-93
Tennessee Jeryl Lynn 1986 78 64-87
Kansas Jeryl Lynn 1988-89 83 57-94
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Mumps Vaccine (MMR) Indications

• All infants gt12 months of age
• Susceptible adolescents and adults without
  documented evidence of immunity

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Measles-Mumps-Rubella Vaccine

• 12 months is the recommended and minimum age
• MMR given before 12 months should not be counted
  as a valid dose
• Revaccinate at gt12 months of age

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Mumps Immunity

• Born before 1957
• Documentation of physician-diagnosed mumps
• Serologic evidence of mumps immunity
• Documentation of adequate vaccination

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Second Dose Recommendations

• First dose of MMR at 12-15 months
• Second dose of MMR at 4-6 years
• Second dose may be given any time gt4 weeks after
  the first dose

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Second Dose of MMR Vaccine

• Intended to produce immunity in persons who
  failed to respond to the first dose (primary
  vaccine failure)
• May boost antibody titers in some persons

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Updated ACIP Recommendations

• Changes in evidence of immunity through
  vaccination
• 1 dose children 1-4 years and low risk adults
• 2 doses school aged children, students in post
  high school educational facilities, international
  travelers and workers in health care facilities
• Health facility workers without other evidence of
  immunity
• 2 doses routinely
• Birth before 1957 consider one dose in non
  outbreak setting and strongly consider 2 doses
  during outbreak
• Outbreak control recommendations
• 2nd dose for children 1-4 years and low risk
  adults if affected by outbreak

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Why mumps, why mid west US and why now?

• Unrecognized importation(s) (student visitors
  from UK or elsewhere?)
• Delayed recognition outbreak
• Physicians not familiar with clinical illness
• Vaccine modified disease?
• Some early cases ruled out with negative IgM
• College settings
• High transmission potential
• Lower 2 dose vaccine coverage than schools
• Poor adherence to isolation guidelines?

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Why mumps, why mid west US and why now?

• 2 doses and 90 vaccine effectiveness may
  result in accumulation of susceptible persons
  sufficient to sustain transmission and a sizeable
  outbreak on a periodic basis
• Contribution of waning immunity?
• Transmission from mumps infections and mild
  illness presentations (vaccine modified disease)?

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However

• High MMR vaccine coverage levels and vaccine
  effectiveness likely prevented thousands of
  additional mumps cases (9 out of 10 exposures
  that may have resulted in infection in 2 dose
  vaccinees prevented)
• Incidence relatively low
• Disease may be modified
• Complications and hospitalizations?