Pertussis Update Linda Bethel, RN, MPH Epidemiology and Immunization Services Branch

Pertussis Most poorly controlled vaccine-preventable disease –Cyclical: Peaks every 2-5 years Adults are vulnerable –27% of reported cases in 2004 were adults –Immunity is not lifelong, wanes 4-12 years after DTaP series and 4-20 years after natural infection Tdap (for adolescents and adults) licensed in 2005 –In 2008 ~40% of adolescents and ~6% of adults had been vaccinated *Wendleboe et al. Infect Dis J 2005;24 (Suppl 5):S58-61.

Pertussis, continued Transmission occurs by close contact via droplets Very contagious: approximately 90% of susceptible household contacts become infected 92-95% of population must be immune to eliminate transmission. * Weiss and Hewlett. Ann Rev Microbiol. 1986;40:661-86

Symptoms Three stages (catarrhal, paroxysmal, and convalescent) lasting 4-12 weeks Typical symptoms: –Paroxysmal cough –Lack of fever –No systemic illness –Post-tussive vomiting –Inspiratory (post-tussive) whoop

Pertussis in Young Infants Initially mild cough, no fever, runny nose Develops into serious symptoms: –Gagging, gasping –Apneic episodes (face may turn red or purple) –Post-tussive vomiting –Seizures –Respiratory distress –Pneumonia

Pertussis Transmission to Infants Adults transmit pertussis to infants –Among 264 known source-cases: Almost 50% were parents, most often mothers 51% were adults >19 years of age Bisgard KM, et al. Infant pertussis: who was the source? Pediatr Infect Dis J 2004; 23(11): Wendelboe AM, et al. Transmission of Bordetella pertussis to young infants. Pediatr Infect Dis J 2007; 26(4):

Pertussis Cases California (as of 9/7/10): –3,834 cases –9.8 cases/100,000 –Most cases since 1958, highest incidence since 1962 –9 infant deaths, all <2 months old San Diego (as of 9/13/10): –514 cases –1 infant death

Number of reported cases by year of onset – California * * year cases cases per 100,000 Cases Rate per 100,000 * As of 9/7/2010. California Department of Public Health, Immunization Branch

San Diego County Pertussis Annual Total Cases by Year of Report, 1999 – 2010 YTD (as of 9/13/2010) Prepared by County of San Diego, Health & Human Services Agency, Public Health Services, Epidemiology & Immunization Services, 9/13/2010

Epidemic curve of reported pertussis cases and deaths by month of onset -- California, 2005, *

Prepared by County of San Diego, Health & Human Services Agency, Public Health Services, Epidemiology & Immunization Services, 9/7/2010

Prepared by County of San Diego, Health & Human Services Agency, Public Health Services, Epidemiology & Immunization Services, 9/13/2010

Pertussis Mitigation Promote the use of Tdap - particularly in those who have contact with infants –Free vaccine through 12/31/2010 for birth hospitals with postpartum Tdap policies; encourage ED use of Tdap –Work with payers re: Tdap reimbursement –CDPH expanded Tdap recommendations Clinician education –CDPH Tdap recommendations –Pertussis signs and symptoms –Treatment recommendations for infants with severe pertussis –Accelerated DTaP schedule for infants Public education –Vaccination/cocooning –Pertussis signs and symptoms –Keep ill people away from infants California Department of Public Health, Immunization Branch

New CDPH Tdap Recommendations Immunize pre-teens and adults with Tdap –7-9 years old who are underimmunized –Those > 10 years of age who have not yet received Tdap, especially: Women of childbearing age, preferably before, or else during or immediately after pregnancy Others with close contact with young infants Health Care personnel Includes persons > 64 years of age No minimum interval between Td and Tdap

Why here, why now? A sufficient number of susceptible people have accumulated in the population via birth cohorts of unvaccinated infants, waning population immunity from vaccine or disease (and less chance for boosting opportunities), parental choice not to vaccinate children, etc. The 2005 epidemic was nationwide, but although other states have reported pertussis increases this year, none have reported increases like those seen in California Some have speculated that California may have less population immunity than other states because it is one of only 11 states that does not have a Tdap requirement for middle school students, however, 2009 National Immunization Survey data indicates that estimated Tdap rates in California adolescents (53.1%) are not much lower than the national estimate (55.6%) California Department of Public Health, Immunization Branch

Pertussis Booster Requirement

Pertussis Cases in children and adolescents aged 0-18 years, by vaccine history – California, 9/7/2010 California Department of Public Health, Immunization Branch

Countering Vaccine Myths The majority of people who get disease have been vaccinated This is explained by two factors: –no vaccine is 100% effective (most childhood vaccines are effective for 85% to 95% of recipients); and –most people in the U.S. are vaccinated When most people have been vaccinated, most cases of disease will occur in vaccinated people. Those who are vaccinated and did not respond to the vaccine often outnumber those who are not vaccinated California Department of Public Health, Immunization Branch

Pertussis Resources

Updated Flyer For Providers

For the Public in English & Spanish

For Schools

Link to Pertussis Materials

Resources California Department of Public Health Immunization Branch (CDPH) – – fault.aspx fault.aspxhttp:// fault.aspx County of San Diego Immunization Program – –Linda Bethel, RN, MPH (619)

Questions?