The Bay Area is in the middle of a whooping cough outbreak, with six times as many cases so far this year as last year, and public health officials are encouraging new parents to get vaccinated and avoid large crowds to protect their infants.

The entire state is seeing large increases in whooping cough, which is the familiar name for pertussis. So far five infants - all of them under 4 months old - have died in California, and all of them caught the disease from their mother or another caregiver.

None of the deaths have been in Northern California, but the Bay Area had 173 cases of whooping cough between January and the end of May, compared with 29 cases in the same period last year, according to the state public health department. Kaiser Permanente, the largest health care provider in the Bay Area, has seen 17 times more cases of pertussis in Northern California so far this year than last year.

"We would like to see everybody get immunized against pertussis - adolescents, adults, everyone. It's especially important for those around newborn infants," said Dr. John Talarico, chief of the immunization branch for the state public health department.



Whooping cough, which gets its name from the noise children make when they gasp for breath between violent coughs, is a respiratory infection that can be deadly in babies. It is usually just an annoying illness in older children and adults, although it can turn into bronchitis or other lung infections.

Natural cycle


The recent rise in whooping cough is probably due to the cyclical nature of an infectious disease: A large group of people gets sick and experiences a short period of immunity, and five or so years later, enough people have lost their immunity that the disease is able to spread freely again.

Pertussis was once thought to be on its way toward disappearing, like many once-widespread diseases that are now prevented with vaccines. But the whooping cough vaccine doesn't provide lifelong protection.

Babies start getting vaccinated at age 2 months and are considered fully protected by the time they enter kindergarten, but children probably lose their immunization by high school. Almost all adults are susceptible to the disease - and in fact, unprotected adults are "the reservoir" of infection that can spread to vulnerable babies, said Dr. Stephen Parodi, chief of infectious disease for Kaiser Permanente Northern California.

"We traditionally thought of pertussis as a children's disease, and that's who's been vaccinated in the past," Parodi said. "By the time we're young adults, we basically don't have immunity. That puts our young children at risk for getting exposed to it."

A vaccine for adults and older children became available in 2005 - it's known as the Tdap, and combines a pertussis vaccine with the tetanus booster shot adults should get every 10 years.

California public health officials are pushing programs to vaccinate all parents who have a baby. Vaccinations typically cost $67 in San Francisco. However, a coupon offering a discounted pertussis vaccination is given to anyone who picks up a birth certificate for a new baby.

Avoid crowds

Parents with newborns also might want to avoid large crowds for at least the first few months during the whooping cough outbreak, said Kathy Harriman, an epidemiologist with the state's public health immunization branch.

"It's probably not the greatest idea to take a new infant out amongst crowds, where you can't control who's around your infant, and people like to come up and take a look," Harriman said.

Doctors also stressed that parents of newborns check in with a pediatrician if a baby shows even mild symptoms of whooping cough, which resemble cold symptoms. The disease is easily treated with antibiotics, but by the time babies develop the obvious "whooping" noise in their cough, they are often very ill already.

"Infants who are infected initially don't look really sick," Harriman said. "They don't have a fever, they might have a runny nose, their cough might not be that noticeable. With a really young infant, I would err on the side of caution."


Symptoms of whooping cough

-- Initially, symptoms are similar to the common cold, and include runny nose, sneezing, red and watery eyes, and a dry cough.

-- After a week or two, severe coughing attacks may occur. Some individuals may develop a persistent hacking cough. For others, the coughing may be serious enough that patients bring up thick phlegm, vomit, turn red or blue in the face and become extremely fatigued. This is when the high-pitched "whoop" sound that defines the disease may become apparent.

-- Parents with infants should consult their pediatrician if their baby develops even mild cold symptoms in the middle of a whooping cough outbreak.

Whooping cough outbreak

California, and the Bay Area in particular, has seen a dramatic increase in whooping cough cases this year. Here are the statistics through May 31 compared with the same period in 2009:

California: 190 cases, no deaths in 2009; 584 cases, five deaths in 2010

Bay Area: 29 cases in 2009; 173 cases in 2010 (no deaths)

San Francisco had 20 confirmed or suspected cases of pertussis in all of 2009; it had 15 cases by May 27 this year. Alameda County had 33 cases in all of 2009 and 26 cases through May of this year.

source: http://topnews.co.uk/26001-number-patients-infected-whooping-cough-comparatively-more-year, http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2010/06/04/BALJ1DPMRJ.DTL