Whooping cough is a respiratory infection caused by the Bordetella pertussis bacterium. An airborne disease that can also be spread through direct contact, it infects infants when someone with the disease breathes on them or coughs or sneezes in close proximity to them.
Before widespread use of the pertussis vaccine, which became available in the 1940s, the disease killed more than 5,000 people in the United States each year. By 1976, the number of cases had decreased by more than 99%. The disease is still cyclical, however, said Ken August, a spokesman for the California Department of Public Health, leading to a spike in cases every five years or so. The last peak year was 2005; then there were 3,182 cases and 18 deaths in the state of California.
FOR THE RECORD:
Pertussis vaccine: An article in the July 12 Health section about whooping cough referred to the booster shot for adults and adolescents as the DTaP vaccine. That is the vaccine for infants; the booster is called the TdaP. —
The hallmark symptom of the disease — in older children and adults, that is — is a severe coughing spell that causes an infected person to make a "whoop" sound as they try to catch their breath after the spell is over. From that sound, the term "whooping cough" was derived.
What are the symptoms?
The symptoms vary by age.
For infants and children younger than 2, early symptoms include a runny nose and cough, which often are dismissed as being caused by a cold. As the illness progresses, the symptoms can become more severe and may include bursts of deep, rapid coughing, thick mucus, and post-cough vomiting. Complications can include pneumonia and seizures.
Those younger than 6 months don't make the characteristic "whooping" sound and thus their illness is especially likely to go undiagnosed. In the latter stage of the disease, the symptoms may increase in severity and may also include cyanosis, a blue discoloration around the fingernails and lips. By this time, the infant's condition is usually dire.
FOR THE RECORD:
Pertussis vaccine: In Monday's Health section, an article about whooping cough referred to the booster shot for adults and adolescents as the DTaP vaccine. That is the vaccine for infants; the booster is called the TdaP. —
Symptoms are most pronounced in children between the ages of 2 and 10 because they're more likely to make the traditional sounds associated with whooping cough.
Adults and teenagers exhibit less noticeable symptoms, usually a cough that lasts for one or two months and feelings of suffocation or not being able to catch one's breath.
Is it possible to have the disease but not know it?
Yes, and it is especially common for adults to be undiagnosed.
Dr. John Talarico, chief of the immunization branch at the California Department of Public Health, says that 15% to 20% of adults who have had a cough for longer than a week likely have pertussis.
Because adult cases of pertussis are rarely fatal, many adults do not worry about getting vaccinated against the disease, as it is often not considered a great danger. However, because it is a contagious disease, an untreated adult can transmit the disease, posing a risk to non-afflicted people.
Who is most likely to become seriously ill from the disease?
Infants less than a year old are the most at risk, especially those younger than 3 months. They are most likely to contract the illness from family or house members. According to a study by the State Surveillance Immunization Branch, 41% of infants infected with pertussis contracted the disease from a sibling, 38% from their mother and 17% from their father.
To protect unvaccinated infants, health officials recommend that anyone who will come into contact with the newborn — parents, siblings, family, caregivers, etc. — get vaccinated. This strategy is known as "cocooning."
But as Talarico points out: No one knows when he or she might come into contact with an infant or pass it on to someone who does come in contact with an infant. For that reason, he says, everyone should be vaccinated.
"Although the danger is highest amongst infants, this does not mean that adults should not get vaccinated. Even if there is no infant in your family, if you are an adult and you have not had a booster shot, you should get one," he said.
Reducing the number of deaths caused by the disease is the most pressing issue, but reducing the number of whooping cough cases is a means to that end.
How many people have contracted the disease or died from it this year?
In Los Angeles County, there have been 88 confirmed cases of pertussis so far this year, with 31 cases currently under investigation — which is already more than half the number cases (156) confirmed for 2009. There have been two infant deaths in Los Angeles County and five deaths statewide, as of June 30. Last year there was only one death in Los Angeles County.
How is it treated?
Most adults and older children recover from the disease on their own after a few months; however they can be treated with antibiotics both to cure the disease and to stop the spread of infection to unvaccinated people.
Does the vaccine provide lifetime immunity?
No. The question of how frequently an adult should get a booster shot is still unknown; however Talarico said that the likelihood that this vaccine provides lifelong immunity is not guaranteed.
Who should get the pertussis vaccine? How often?
Everyone should get the vaccine because everyone is vulnerable, Talarico said. Infants must wait until they are 2 months old to receive their first vaccination, after which state health experts recommend they get subsequent booster shots at 4 months, 6 months, 15 to 18 months, and 4 to 6 years of age. Adults and adolescents (children older than10 years) should get a booster shot of the vaccine, known as DTaP, at least once.
Talarico says that one vaccine administered during adulthood is likely adequate to protect someone for life, but that it a second shot later in life wouldn't necessarily be a bad idea.
Dr. Robert Kim-Farley, director of communicable disease prevention and control for the Los Angeles County Department of Public Health, recommends that unvaccinated adults get their shot the next time they go to the doctor to get their 10-year tetanus booster shot. Because the pertussis vaccine is a combination vaccine for pertussis, tetanus and diphtheria, adults should opt for this combination vaccine, instead of the singular tetanus vaccine, he says.
Should anyone avoid the vaccination?
People who have progressive neurological disorders, who are allergic to the vaccine or who have had a serious reaction to the vaccine as an infant or child should not get the vaccine.
Do you need to get a booster shot if you have already had the whooping cough?
Yes. Even if you had it as a child and survived the illness, you still need a booster shot as an adult.
What are the side effects of the vaccine?
The side effects of the vaccine are mild and are generally limited to mild fever or pain at the injection site. Kim-Farley urges concerned parents to worry less about the vaccine's side effects and more about what can happen if their infant or child does not get vaccinated.
Where can one get the vaccine?
Public and private healthcare providers offer the vaccine. To find a healthcare site that offers the vaccine, dial 2-1-1 or visit http://www.publichealth.lacounty.gov/ip. The federal Vaccines for Children Program also offers vaccines free of charge to uninsured children.