Health Advisory
Pertussis Update
To: Health Care Providers, Hospitals, Ambulatory Care Centers
From: Susan Schoenfeld, Deputy State Epidemiologist for Infectious Disease
Date: January 26, 2012
– Please Distribute Widely –
Pertussis 2011: 94 cases of pertussis were confirmed in Vermont. This is still a provisional total and may increase slightly. Among 80 children between the ages of 2 months and19 years with confirmed pertussis, 32.5 percent were unvaccinated or not up to date for age. Most cases (70%) occurred in Chittenden County in November and December.
January 2012: As of January 25, 26 cases have been confirmed in Chittenden (14), Washington (6) Grand Isle (2), Addison (2), Orleans (1), and Windsor counties. Many others are under investigation.
Information for clinicians
Expanded information for clinicians about pertussis has been added to the Health Department’s website: http://healthvermont.gov/prevent/pertussis/providers.aspx.
The information below includes highlights from the Dec. 16, 2011 pertussis conference call and from materials at that web location.
Think of pertussis.
Consider pertussis as a diagnosis for anyone who has the following symptoms, regardless of vaccination history:
- A cough in a person who has been notified of a close exposure to pertussis, including anyone who has been notified of potential exposure at school or other setting.
- A paroxysmal cough of any duration, with whooping, post-tussive vomiting/gagging or apnea, or apnea or cyanosis without the characteristic paroxysmal cough, especially in infants.
- Prolonged cough. Coughing illness that lasts more than a week (during periods of increased pertussis illness).
- Have a lower threshold for considering pertussis when the patient has close contact with an infant or others at high risk for pertussis complications.
Report suspected cases to the Health Department’s Epidemiology Unit at 802-863-7240.
Test for pertussis.
- Collect a specimen using a nasopharyngeal (NP) swab applicator with a flexible shaft.
- Gently insert the swab into one of the nares and proceed to the posterior wall of the pharynx.
- Don’t direct the swab upward or force the swab past obstruction.
- Turn the swab a quarter of a turn and hold in place until a paroxysmal cough is elicited, or ask patient to cough. (This ensures an adequate specimen and reduces the possibility of false negative results.)
- Insert NP swab into Regan-Lowe transport medium, ensuring the tip is completely covered.
- The Health Department recommends ordering both PCR and culture when feasible.
- The Health Department Laboratory can run both tests from one specimen, but both tests must be requested on the lab requisition form: http://healthvermont.gov/prevent/pertussis/providers.aspx#Laboratory or ask for information from the laboratory you use.
Do not test if there are no symptoms.
For questions about testing or to order specimen collection kits, call the Health Department Laboratory at 802-863-7335.
|
Interpreting
Test Results |
||
|
Test |
Timing of specimen collection |
Test result interpretation |
PCR PCR(results within 24-96 hours of receipt at laboratory) |
Collect specimens as early as possible
after cough onset. PCR will detect non-viable organisms present, even in
persons who have been treated with antimicrobials; however, false negatives can occur and are more common later in the illness or after
start of antibiotics. |
(+) Positive: Confirms B. pertussis if patient has
cough greater than 2 weeks and either paroxysmal coughing, post-tussive
vomiting, or whooping. (-) Negative:
Does not rule out B. pertussis
infection; consider other factors. |
Cult Culture(results can take up to 7 days) |
Collect specimens as early as possible
after cough onset. Recovering the organism is unlikely beyond 3 weeks of
cough or in patients who have received antimicrobials. False negatives are common even early in illness. |
(+) Positive:
Confirms B. pertussis
infection. (-) Negative:
Does not rule out B. pertussis
infection; consider other factors. |
Treat and report suspected and confirmed cases.
Treatment guidelines are available on the Health Department website: http://healthvermont.gov/prevent/pertussis/documents/pertussistreatment.pdf
- Patients with suspected pertussis should be treated and advised to stay home for five days, even before getting a test result, or even if a test is not done. Close household-type contacts should receive chemoprophylaxis. Empiric treatment is especially recommended if there are high-risk contacts in household (infant, pregnant woman, etc).
- If 21 days have already elapsed since onset of cough, treatment is not recommended because it will not improve outcome.
- Prescribe antimicrobial prophylaxis (same regimen as treatment) to people who are close contacts of pertussis cases. Symptomatic contacts should be evaluated for pertussis.
- Antimicrobial prophylaxis is recommended if exposure to an infectious case occurred within the previous 21 days (the maximum incubation period for pertussis).
- Asymptomatic contacts receiving prophylaxis should not be excluded from their usual activities.
For questions about treatment, call the Health Department’s Epidemiology Unit at (802) 863-7240.
Stop Transmission.
- Exclude. Inform patients with suspected pertussis to stay at home and avoid close contact with others until they have completed the fifth day of an appropriate antibiotic - OR - had cough symptoms for at least three weeks.
- Vaccinate. Vaccination is the best protection against pertussis. Because immunity from childhood pertussis vaccination wanes over time, the adolescent/adult pertussis booster vaccine (Tdap) for adolescents and adults is essential to reduce the risk of contracting pertussis, and can decrease severity of disease. Vaccinating adolescents and adults, especially family members or caregivers of infants and health care workers, can help prevent pertussis transmission to infants too young to be vaccinated.
One dose of Tdap vaccine is recommended for people 11 years and older. There is no minimal time interval between doses of Td and Tdap.
Specific indications for Tdap in those who are high-risk:- Children age 7 to 10 who have not completed the five dose DTaP series
- Pregnant women during the third or late second trimester (after 20 weeks)
- Adults over 64 years who anticipate contact with infants
- Health care providers
For information about ordering vaccine, call the Health Department’s Immunization Program at 802-863-7240.