Many California physicians are blaming low vaccination coverage -- especially among adolescents and adults -- for the state's pertussis epidemic and point to their own financial disincentives as part of the reason.
And they're looking to the state legislature to mandate better reimbursement for vaccinations.
As of June 15, the California Department of Public Health had confirmed 910 cases in the state in 2010 and another 600 were under investigation. Case counts were about quadruple what had been seen in 2009, the department indicated, prompting its director to declare an epidemic.
A smaller total has been reported to the U.S. Centers for Disease Control and Prevention, according to this week's Morbidity and Mortality Weekly Report. It listed 633 cases as of July 3, but that is still nearly triple the 233 seen in California at the same time in last year.
Despite the discrepancy, California is clearly having a major outbreak. A few other states have also reported significant increases in pertussis cases, including Arizona, Colorado, Montana, Oregon and South Carolina, but not to the same extent as the Golden State, according to the CDC.
Gaps in California's vaccination requirements for schoolchildren have been widely cited as a major factor, but family doctors in the state have also pointed to inadequate insurance reimbursement for vaccinations as another problem.
According to the California Academy of Family Physicians (CAFP), "Health plans generally cover at best the cost of vaccines, but not obtaining, storing (a complicated process), and administering the vaccines."
As a result, the CAFP said many doctors don't stock vaccines. Instead, they refer patients to community clinics and grocery and drugstore chains that offer vaccinations. "There's no way to know whether a patient actually follows through," the CAFP indicated in a statement, also noting that insurers may not cover vaccinations in these settings.
The CAFP is backing legislation now before California lawmakers that would require insurers to reimburse physicians for the full cost of buying and administering vaccines.
It would also prohibit patient copays for vaccine administration and dollar limits on childhood and adolescent immunizations.
Dr. Patricia Samuelson, a physician in a small family practice in Sacramento, told MedPage Today in an interview arranged by the CAFP that the publicity about the state's pertussis epidemic hadn't driven many more of her patients to seek vaccination for themselves or their children.
She said there's been an increase, "but not as much as I would have liked."
Gaps in vaccination coverage are the major reason for this year's epidemic, Samuelson said, on top of a cyclical spike that is a familiar feature of pertussis.
California is one of only 11 states that does not require pertussis boosters for children of middle-school age. Samuelson said low immunization rates among adolescents and adults -- more so than infants -- were largely to blame for the current situation.
"Adults and adolescents are clearly the source," she told MedPage Today. She described seeing one infant with severe pertussis who, it transpired, had been cared for by a grandmother with a mild cough.
She said lack of insurance was, in turn, an important reason for patients to go unimmunized. "A huge proportion of California is uninsured," she said.
Nationally, pertussis case counts are actually lagging behind the 2009 tally at this point in the year: 5,999 versus 6,986, according to the July 9 MMWR.
But Samuelson cautioned that the factors she believes are driving the California spike are present in other states, too.
"They haven't seen [a spike] yet," she said, emphasizing the last word.
She also noted that healthcare providers can transmit the disease, recommending that physicians and others make sure their own vaccinations are up to date.