Charles Stewart MD EMDMProfessor 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 time-consuming

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%20Department%20(DEP)/attachments/Health_Alert_Pertussis_07-27-2010.pdf

© Illustration Bruno Laporte