A public health nurse gives an immunization injection.

In 2010, California public health authorities struggled with a record whooping cough epidemic. 9,156 cases were reported and ten infants died. A pertussis vaccine exists but California is a state that allows parents to exempt their children from immunizations due to a strong personal belief.
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NOTE: This is a post that is several years old. To follow the 2012 whooping cough outbreak, please see our work on Examiner. Those stories may also be found on the sidebar on the left.
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Whooping cough, or pertussis, continues to spread in many areas of the country. In other areas, the case counts are down dramatically from 2009. The best count, using both the data provided in the Centers for Disease Control (CDC) MMWR Week 27 report (as of July 10, 2010) and a press release from the California California Department of Public Health (CDPH), seems to be 7,174 cases in 2010, and 7,440 cases for 2009 through the same date.

The CDPH press release is cited for a reason. Just over half of all the cases of whooping cough in California have not been reported to the CDC. I have been following with the CDC on this issue and they forwarded to me this response from California, that had been forwarded to them:

We are counting cases that are coming from CDMS and from the raw file you are exporting. It is my understanding that only cases for which we’ve received a Case History Form are sent to CDC from CDMS. Many counties are extremely behind in submitting the form since they are overwhelmed with case investigation for the ongoing outbreak. We’ve been maintaining our in-state total to release to the media which we know doesn’t match up with what is being sent to CDC. Our total count of Pertussis cases reported Jan-June 2010 is 1,337.

The press released linked has increased that June 30 total to 1,496. Here is a graph illustrating the difference in reported numbers. Click on the graph for a larger image.

The inability of California to report its cases of whooping cough in a timely manner means that Federal public health officials cannot react in a timely manner to changes in the case counts. It should worry neighboring states, as well, since they, too, cannot know how severe the epidemic may be.

Here are the states, in decreasing order of 2010 pertussis cases, that make up 2/3 of all the cases of whooping cough in the United States.

The states in deep red are up at least 150% over 2009. The cases in salmon are up between 100% and 150% over last year. Despite their totals, Texas and Ohio are only up 8% over 2009. Arizona, however, is up 86% and upstate New York (everything outside New York City) is up 98% over 2009 at this time. Click on the graph for a larger image.

These nine states have seen 2/3 of the cases of pertussis. Only California is seeing a dramatic increase in case numbers, year over year. Upstate New York has gone to 190 cases in 2010 from 96 cases in 2009, for example. The public health authorities in California called it an epidemic, and the case number increase bears out that declaration.

While those states are seeing significant increases in cases of whooping cough for 2010 over last year, others have significant decreases. Here are the states with over 150 cases in 2009 and with reductions in cases year over year.

For more information about whooping cough:

Pertussis (Whooping Cough) – What You Need To Know from the CDC

Pertussis (Whooping Cough) from CDPH