There have been 5,272 confirmed, probable and suspect cases of whooping cough (pertussis) reported in California this year up to October 5, according to the California Department of Public Health; a rate of 13.5 cases per 100,000 across the state. 5,249 of them started showing whooping cough symptoms in 2010.

Over the last week there have been 811 new reported cases, however, authorities inform that a significant proportion are previous incident cases from Los Angeles County.

The cases have been classified as approximately 66% confirmed, 17% probable and 17% suspect.

This is the highest number of cases in 60 years – in 1950 there were 6,613 cases reported. With nearly three months to go, there is a good chance 2010 will break that record.

The last time the current incidence of 13.5 per 100,000 was surpassed was in 1959 when a rate of 16.1 cases per 100,000 was reached.

California Department of Public Health informs that:

  • 11% of all whooping cough cases, where information is available, were hospitalized.
  • 59% of those admitted to hospital were aged 3 months or less.
  • 74% of patients hospitalized with whooping cough were aged 6 months or less.
  • 9 whooping cough patients are known to have died, of which 8 were Hispanic infants.
  • 8 of those who died were aged 2 months or less when symptoms appeared. None of them had received any pertussis vaccines.
  • One of those who died was a 2 months old and had received an initial dose of DTaP 15 days before symptoms appeared. The baby had been born premature (28 weeks).
  • Most of the babies who became infected with whooping cough were aged 3 months or less.
  • 261.3 babies aged 6 months or less in every 100,000 became infected with whooping cough.
  • 40.2 children aged 7 to 9 years in every 100,000 became infected with whooping cough.
  • 30.1 children aged 10 to 18 years in every 100,000 became infected with whooping cough, the majority of which were aged 10-11 years.
  • 13.4 Hispanics of all ages in every 100,000 became infected with whooping cough
  • 11.8 Caucasians of all ages in every 100,000 became infected with whooping cough
  • 322.7 Hispanic babies aged 6 months or less in every 100,000 became infected with whooping cough

Below is a breakdown of reported cases of whooping cough in California by area up to October 5:

  • CALIFORNIA – cases 5272 – rate 13.47 (per 100,000)
  • ALAMEDA – cases 221 – rate 15.42
  • City of Berkeley* – cases 9 – rate 8.40
  • ALPINE – cases 0 – rate 0.00
  • AMADOR – cases 3 – rate 7.53
  • BUTTE – cases 22 – rate 9.70
  • CALAVERAS – cases 7 – rate 14.83
  • COLUSA – cases 9 – rate 38.62
  • CONTRA COSTA – cases 123 – rate 11.55
  • DEL NORTE – cases 16 – rate 52.23
  • EL DORADO – cases 40 – rate 21.47
  • FRE SNO – cases 374 – rate 38.77
  • GLE NN – cases 0 – rate 0.00
  • HUMBOLDT – cases 32 – rate 23.88
  • IMPERIAL – cases 8 – rate 4.33
  • INYO – cases 2 – rate 10.48
  • KERN – cases 287 – rate 33.64
  • KINGS – cases 21 – rate 13.04
  • LAKE – cases 3 – rate 4.50
  • LASSEN – cases 0 – rate 0.00
  • LOS ANGELES** – cases 707 – rate 7.21
  • City of Long Beach* – cases 48 – rate 9.74
  • City of Pasadena* – cases 11 – rate 7.32
  • MADE RA – cases 109 – rate 68.88
  • MARIN – cases 310 – rate 122.28
  • MARIPOSA – cases 10 – rate 52.81
  • MENDOCINO – cases 25 – rate 27.04
  • MERCED – cases 102 – rate 38.10
  • MODOC – cases 0 – rate 0.00
  • MONO – cases 5 – rate 34.27
  • MONTEREY – cases 32 – rate 7.43
  • NAPA – cases 19 – rate 13.49
  • NEVADA – cases 19 – rate 18.66
  • ORANGE – cases 325 – rate 10.19
  • PLACER – cases 47 – rate 13.79
  • PLUMAS – cases 2 – rate 9.20
  • RIVERSIDE – cases 224 – rate 10.28
  • SACRAMENTO – cases 90 – rate 6.26
  • SAN BENITO – cases 3 – rate 4.80
  • SAN BERNARDINO – cases 58 – rate 2.71
  • SAN DIEGO – cases 464 – rate 14.64
  • SAN FRANCISCO – cases 83 – rate 10.19
  • SAN JOAQUIN – cases 53 – rate 7.32
  • SAN LUIS OBISPO – cases 364 – rate 135.84
  • SAN MATEO – cases 111 – rate 15.12
  • SANTA BARBARA – cases 47 – rate 10.91
  • SANTA CLARA – cases 254 – rate 13.93
  • SANTA CRUZ – cases 58 – rate 21.74
  • SHASTA – cases 18 – rate 9.52
  • SIERRA – cases 0 – rate 0.00
  • SISKIYOU – cases 7 – rate 14.94
  • SOLANO – cases 14 – rate 3.21
  • SONOMA – cases 209 – rate 42.53
  • STANISLAUS – cases 106 – rate 19.29
  • SUTTER – cases 4 – rate 4.00
  • TEHAMA – cases 1 – rate 1.55
  • TRINITY – cases 0 – rate 0.00
  • TULARE – cases 103 – rate 22.56
  • TUOLUMNE – cases 9 – rate 15.40
  • VENTURA – cases 20 – rate 2.36
  • YOLO – cases 20 – rate 9.87
  • YUBA – cases 4 – rate 5.10

    • *City health jurisdictions not included in county total
    **Includes cases reported to LAC DPH as of 9/17/2010

Whooping cough, medically known as pertussis is a highly contagious respiratory infection caused by Bordetella pertussis, a bacterium. Hallmark symptoms include a violent and uncontrollable cough. The cough can become so severe that some patients have breathing difficulties during a fit.

Coughing fits often result in the patient making a whooping sound as they gasp for air, hence the name. Coughing fits can be present for 10 weeks or longer. Whooping cough is also called the 100 day cough.

As the Californian figures show, young children and babies are particularly susceptible to complications, with very young infants having a higher risk of death.

Health care professionals say the best protection from pertussis is to be vaccinated. Vaccines exist for children, teenagers and adults.

Source: California Department of Public Health

Written by Christian Nordqvist