Transcript Pertussis Epidemic

Charles Stewart MD EMDM
Professor of Emergency Medicine
Introduction:
Everyone gets/can get Pertussis
Immunity from vaccination is not 100%
California is seeing more cases than before vaccination
started in 1947.
Increased testing?
Increased # of cases
Differences:
Bronchiolitis
Brief - Few days max
Progress to lower
respiratory tract
involvement
PE - Lower tract
involvement
Pertussis
Longer
No progression to lower
tract involvement
More classic ‘whooping’
cough - rare very sick
One of the most common childhood illnesses in the U.S. in
the 20th century
Before vaccination > 200,000 cases/year
Since vaccination in 1940's, > 80% decreased incidence
Still an endemic infection in the U.S. (not "vaccine
eradicatable")
Increasingly prevalent
*Highest morbidity in young children
Why does it matter now?
Significantly increasing prevalence in the U.S., particularly in
certain states (such as California)
Pertussis usually manifests itself slowly, like a mild cold, with
a runny nose or mild cough but can steadily progress into
coughing fits resulting in its telltale “whoop.
California...
The anti-vaccination folks had a real ‘win’ here!
Pertussis In Adolescents and Adults
Often milder than in infants and children
May be asymptomatic, or may present as classic pertussis
Persons with mild disease (we never know they have it)
may transmit the infection to others
Older persons often the source of infection for children
Pertussis In Adolescents and Adults
Reported (perhaps not actual) incidence by age decreases
as age goes up
Highest (reported) incidence in young children
Decreased (reported) incidence decreases with each
DTaP vaccination (2 - 4 - 6 months)
Symptoms...
Diagnosis of Pertussis
High clinical suspicion (but only the right patients)
Cough > 2 weeks
No significant fever
Post-tussive emesis
Close contact with others with prolonged cough
Looks fine in the ED (no sig. sx's) -- i.e. DO NOT
CLINICALLY HAVE BRONCHIOLITIS
Testing
Culture is gold standard, though expensive and timeconsuming
PCR is faster with good sensitivity
Classic WBC elevation with lymphocytosis only occurs in
infants and is unreliable (DO NOT CHECK CBC TO
ESTABLISH OR SUPPORT DX.)
Testing
Who to Test?
Cough > 2 weeks
Coughing "fits"
No significant fever
Post-tussive emesis
Close contact with others with prolonged cough
Looks fine in ED
Testing
No rapid test for Pertussis exists.
Test only on good clinical suspicion while waiting the results
to come back.
Who to Treat (while awaiting PCR result) --*Difficult
question
Under 6 months(?), due to risk of immediate complications
if treatment delayed (unlike older children and adults
High likelihood of disease
Treatment of Pertussis
Supportive care
Azithromycin (standard treatment)
Trimethoprim-Sulfamethoxazole (alternative to azithromycin)
Antibiotics do NOT shorten the course of illness, they only
(potentially) reduce contagion
TDaP
Tetanus, Dipthera, Pertussis
All persons > 10 years old considered susceptible to pertussis
due to waning immunity unless given single dose of TDaP
*Single dose of TDaP should now replace Td booster
TDaP
Special emphasis on adults with close contact with infants
(including childcare and ALL healthcare personnel, and
parents)
The purpose of giving everyone TDaP over age 10 is to
decrease the spread of asymptomatic carriers in the
community
Vaccination rates of at least 93% are needed to ensure herd immunity against
pertussis, which prevents the disease from spreading quickly to unvaccinated
individuals.
TDaP
Hispanic infants under six months are most affected by the
epidemic of pertussis that affect California, authorities said
Monday health. The epidemic has already caused the deaths
of eight babies, mostly Hispanic, said the Department of
Public Health of California (CDPH, in English), reporting that
cases identified in California totaled more than 200 in the last
week, surpassing the 3,300 so far this year (article date Aug
2010).
Immunization is lacking in this group.
Recent studies have also suggested some mutated strains of
the disease may be resistant to the vaccine, including a paper
published in Emerging Infectious Diseases earlier this year.
Kurniawan J, Maharjan RP, Chan W-F, Reeves PR, Sintchenko V, Gilbert GL,
et al. Bordetella pertussis clones identified by multilocus variable-number
tandem-repeat analysis. Emerg Infect Dis [serial on the Internet]. 2010 Feb
[accessed 12 Jan2011]. Available from
http://www.cdc.gov/EID/content/16/2/297.htm
Summary
Far more common than usually suspected
Must be considered to be diagnosed
Matters mostly for infants
Dramatically increasing in (reported) incidence throughout
the U.S.
You are likely to see it if you look for it!
Does NOT look like bronchiolitis
Further Info
Info: @
http://www.sccvote.org/SCC/docs
/Public%20Health%20Departme
nt%20(DEP)/attachments/Health
_Alert_Pertussis_07-27-2010.pdf
© Illustration Bruno Laporte