HEALTH -- August 21, 2012 at 6:06 PM ET
Whooping Cough Outbreak: Top 10 Things You Should Know
Boy Scouts in Everett, Wash., advertise a whooping cough vaccination clinic during a community gathering in early August. Photo by Jason Kane.
OLYMPIA, Wash. | Whooping cough. Those are among the last words Jennifer Crocker expected to be on her mind during a recent visit to the doctor. But she hasn’t been able to shake all the sound bites she’s heard lately on the local news:
Whooping cough cases have skyrocketed throughout the nation in the last few months, reaching “epidemic” levels in Washington state as of April.
A full 92 percent of adults are no longer inoculated against the disease — in large part because most Americans don’t know that a new booster exists.
And if adults catch pertussis — as the disease is formally known — they can easily transmit it to newborns, who can die from it.
“I didn’t even think about any of this before,” Crocker said, immediately before receiving the pertussis booster in early August. “Not until talking with my sister, who is about to have a baby.”
The confusion is much the same almost anywhere you go in the United States, said Dr. Anne Schuchat, director of the National Center for Immunization and Respiratory Diseases. When whooping cough — pronounced ‘HOOP-ing cough’ — is present in a community, people learn the basics of how to protect themselves and others. When it fades, they forget.
“That’s really the case with so many vaccine preventable diseases — when we’re not seeing them every day we forget about them,” Schuchat said. “But it’s really important that people know this one is spreading all around the country, that we have vaccines and that most adults haven’t gotten vaccinated yet and really do need to.”
Click play on the map below to see how pertussis has impacted your state in the last few years. And below that, read Dr. Schuchat’s “Top 10 Things You Should Know about the Whooping Cough Outbreak.”
PBS NewsHour health correspondent Betty Ann Bowser traveled to Washington state recently to examine some of the factors fueling this year’s epidemic. Tune in to the NewsHour broadcast Wednesday for her full report.
In the meantime, here are the top 10 things that the Centers for Disease Control and Prevention thinks you should know about whooping cough:
1. Whooping Cough Can Be Prevented With Vaccines
Schuchat: Pertussis, or whooping cough, can be prevented with vaccines. Before pertussis vaccines became widely available in the 1940s, about 200,000 children got sick with it each year in the U.S., and about 9,000 died as a result of the infection. Now, we see about 10,000-25,000 cases reported each year and typically 10-20 deaths.
Pertussis vaccines are recommended for people of all ages. Infants and children should get five doses of DTaP for maximum protection. A dose is given at 2, 4 and 6 months, at 15 through 18 months, and again at 4 through 6 years. A booster dose of Tdap is given to pre-teens at 11 or 12 years of age. Any adolescents or adults who didn’t get Tdap as a preteen are recommended one dose. Getting Tdap is especially important for pregnant women and others who will be caring for infants. You can get the Tdap booster dose no matter when you got your last regular tetanus booster shot (Td) — there is no need to wait. Also, you need to get Tdap even if you were vaccinated as a child or have been sick with pertussis in the past.
2. Protecting Infants Is Critical
Schuchat: Infants are at greatest risk for getting pertussis and then having severe complications from it, including death. More than half of infants younger than 1-year-old who get pertussis are hospitalized, and 1 or 2 in 100 hospitalized infants dies. There are two strategies to protect infants until they’re old enough to receive the full benefits of their own immunizations.
First, vaccinate pregnant women with Tdap during their third or late second trimester. By getting Tdap during pregnancy, maternal pertussis antibodies transfer to the newborn, likely providing protection against pertussis in early life, before the baby starts getting DTaP vaccines. Tdap will also protect the mother at the time of delivery, making her less likely to transmit pertussis to her infant. When the source of pertussis was identified, mothers were responsible for 30-40 percent of infant infections.
Second, make sure everyone around the infant is immunized. This includes parents, siblings, grandparents (including those 65 years and older), other family members, nannies, etc. They should get the age-appropriate vaccine (DTaP or Tdap) at least two weeks before coming into close contact with the infant. When the source of infection was identified for infants, it was household members about 80 percent of the time.
It’s also critical that health care personnel are up-to-date with a Tdap booster dose, especially those who care for infants.
3. No Lifetime Protection From Vaccine Or Infection
Schuchat: Getting sick with pertussis or getting pertussis vaccines doesn’t provide lifelong protection, which means you can still get pertussis.
Pertussis vaccines are effective, but not perfect. They typically offer high levels of protection within the first two years of getting vaccinated, but then protection decreases over time. This is known as waning immunity. Similarly, natural infection may also only protect you for a few years.
In general, DTaP vaccines are 80-90 percent effective. Among kids who get all five doses of DTaP on schedule, effectiveness is very high within the year following the fifth dose — at least 9 out of 10 kids are fully protected. There is a modest decrease in effectiveness in each following year. About 7 out of 10 kids are fully protected five years after getting their last dose of DTaP and the other 3 out of 10 kids are partially protected — protecting against serious disease.
Our current estimate is that Tdap vaccination protects 7 out of 10 people who receive it. Since Tdap vaccines were only licensed in 2005, we don’t yet have long-term results of the duration of protection this vaccine gives. We’re still working to understand how that protection declines over time or might differ based on which vaccine was received during early childhood (i.e., DTaP or DTP). CDC will be conducting an evaluation in collaboration with health departments in Washington and California to better understand how long Tdap vaccines protect from pertussis. The data from these evaluations will help guide discussions on how best to use vaccines to control pertussis.
Keeping up-to-date with recommended pertussis vaccines is the best way to protect you and your loved ones.
4. Vaccination Prevents Severe Disease
Schuchat: If you’ve been vaccinated and get pertussis, you are less likely to have a severe infection. In those who have been vaccinated, in most cases, the cough won’t last as many days; coughing fits, whooping, and vomiting after coughing fits occur less often; and fewer children have apnea (life-threatening pauses in breathing), cyanosis (blue/purplish skin coloration due to lack of oxygen) and vomiting.
5. Reported Cases Are Increasing
Schuchat: Since the early 1980s, there has been an overall trend of an increase in reported pertussis cases. Pertussis is naturally cyclical in nature, with peaks in disease every 3-5 years. But for the past few decades, we’ve seen the peaks getting higher and overall case counts going up. There are several reasons that help explain why we’re seeing more cases as of late. These include: increased awareness, improved diagnostic tests, better reporting, more circulation of the bacteria, and waning immunity.
When it comes to waning immunity, it seems that the acellular pertussis vaccine (DTaP) we use now may not protect for as long as the whole cell vaccine (DTP) we used to use. Throughout the 1990s, the U.S. switched from using DTP to using DTaP for infants and children. Whole cell vaccines are associated with higher rates of minor and transient side effects such as fever and pain and swelling at the injection side. Rare but serious neurologic adverse reactions including chronic neurological problems rarely occurred among children who had recently received whole cell vaccines. While studies have had inconsistent results that the vaccine could cause chronic neurological problems, public concern in the U.S. and other countries led to a concerted effort to develop a vaccine with improved safety. Due to these concerns, along with the availability of a safe and effective acellular vaccine, the U.S. switched to acellular vaccines.
6. Vaccine Refusals and Disease Importation Are Not To Blame For Outbreaks
Schuchat: Even though children who haven’t received DTaP vaccines are at least 8 times more likely to get pertussis than children who received all five doses of DTaP on schedule, they are not fueling the large-scale outbreaks or epidemics. However, their parents are putting them at greater risk of getting a serious pertussis infection and then possibly spreading it to other family or community members.
We often see people blaming pertussis outbreaks on people coming to the U.S. from other counties. This is not the case. Pertussis was never eliminated from the U.S. like measles or polio, so there’s always the chance for it to get into a community. Plus, every country vaccinates against pertussis.
7. Not Every Cough Is Pertussis And You May Or May Not “Whoop”
Schuchat: There are a lot of causes behind a person’s cough and not every cough is pertussis. In general, pertussis starts off with cold-like symptoms and maybe a mild cough or fever. But after one to two weeks, severe coughing can begin. Unlike the common cold, pertussis can become a series of coughing fits that continues for weeks. The best way to know if you have pertussis is to see your doctor, who can make a diagnosis and prescribe you antibiotics, if recommended.
The name “whooping cough” comes from the sound people make gasping for air after a pertussis coughing fit. However, not everyone with pertussis will cough and many who cough may not “whoop.”
Teens and adults, especially those who haven’t been vaccinated, may have a prolonged cough that keeps them up at night. For those who do get the coughing fits, it’s the worst cough of their lives. And the cough may last for weeks or months, causing major disruptions to your daily life and complications like broken ribs and ruptured blood vessels.
In infants, they may not cough at all. Instead, they may have long pauses in breathing or struggle to breathe. Any time someone is struggling to breathe, get them to a doctor right away.
8. There’s No Evidence That Strain Changes Are Causing More Cases
Schuchat: CDC is evaluating potential causes of increasing rates of pertussis, including changes in disease-causing strains. Unlike a food-borne illness, where one strain causes an outbreak, multiple strains of pertussis bacteria can be found causing disease at any given time, including during outbreaks. There is a lot of diversity in strains causing pertussis in the U.S. and in Washington. While strains have changed over time, strain changes do not seem to be the cause of the increase in pertussis we’ve been seeing. And there’s no direct evidence that strain changes have reduced the effectiveness of the vaccines. It’s much more likely that waning immunity is the driving force behind the increase in cases.
9. Pertussis Is Very Easy To Spread
Schuchat: Pertussis is very easy to spread from person-to-person through coughing and sneezing. A person with pertussis can infect 12 to 15 other people. That’s why being up-to-date with pertussis vaccines and practicing good cough etiquette are so important.
Many infants who get pertussis are infected by older siblings, parents or caregivers who might not even know they have the disease. If pertussis is circulating in the community, there is a chance that even a fully vaccinated person of any age can catch this very contagious disease.
If you have been vaccinated, the infection is usually less severe. If you or your child develops a cold that includes a severe cough or a cough that lasts for a long time, it may be pertussis. The best way to know is to contact your doctor.
10. We Can’t Rely On Herd Immunity to Control Pertussis
Schuchat: Since pertussis is so easy to spread and protection from vaccination wears off over time, we can’t rely on herd immunity to protect everyone. Herd immunity, or community immunity, is a situation in which a sufficient proportion of a population is immune to an infectious disease through vaccination or prior illness to make its spread from person to person unlikely. Even individuals not vaccinated (such as newborns and those with chronic illnesses) are offered some protection because the disease has little opportunity to spread within the community.
We have a lot of room for improvement with adult vaccination. Fewer than 10 percent of adults have gotten their Tdap booster dose, so we can’t yet measure how well herd immunity could work for pertussis. So it’s even more important that everyone get their recommended pertussis vaccines to protect themselves.
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Do you have questions about the whooping cough outbreak? Ask them in the comments section below or send them to email@example.com or via Twitter at @jasokane. We’ll post answers from the Centers for Disease Control and Prevention on Friday.