Whooping Cough Vaccine Failures Increasing

By September 19, 2012No Comments

Editor’s note: For more than two years, San Diego’s I-Newsource has led the reporting on possibly the worst whooping cough epidemic in half a century. Here in Washington state, the incidence of the disease is more than six times the national average, and on April 3, a pertussis epidemic was declared by the Washington State Secretary of Health. The article below is the work of I-Newsource and KPBS and is republished with permission.

Children across the country may need yet another booster shot — a seventh inoculation — to protect against whooping cough, a disease that is spreading across the nation in what may be the worst epidemic in more than 50 years.

New research confirms the whooping cough vaccine is failing at a higher rate than expected, and scientists are considering adding a seventh dose to the national immunization schedule published by the Centers for Disease Control and Prevention. Two recent studies have found the majority of people getting sick are up to date with their immunizations.

KPBS and Investigative Newsource foreshadowed these findings in an investigation in 2010 when whooping cough cases had reached epidemic proportions in California, killing 10 babies and sickening some 9,000 people.

The investigation raised serious questions about the effectiveness of the vaccine, reporting that a majority of the people diagnosed with the illness in San Diego County and across California had been fully immunized against the disease.

Whooping cough, also known as pertussis, has dropped off in California, but it’s scorching a path through states such as Washington and Wisconsin. Some scientists suggest there is a need for a new vaccine that is more effective and lasts longer.

“I think 2010 was a real eye-opener,” said Dr. James Cherry, a specialist in pediatric infectious diseases at UCLA. “My friends at the department of public health are saying vaccine failures are a much bigger part of this and I agree with them.”

In interviews with KPBS and I-Newsource two years ago, Cherry said he and other scientists attributed the dramatic rise in whooping cough cases in California to increased awareness among physicians, better testing and the fact that outbreaks are cyclical in nature, occurring every about every five years. Officials at the CDC and the California Department of Public Health also blamed people who weren’t up to date with their immunizations for the spread of the disease.

Today, experts have backed away from some of those assumptions.

“We know there are places around the country where there are large numbers of people who aren’t vaccinated,” said Dr. Anne Schuchat, the director for the National Center for Immunization and Respiratory Diseases at the CDC, during a recent teleconference. “However, we don’t think those exemptors are driving this current wave.”

New studies published in prominent medical journals have called into question the 85 percent efficacy quoted in the vaccine’s package inserts. For example, one study by scientists at Kaiser Permanente found vaccine effectiveness in Marin County in 2010 to be between 24 and 79 percent for children 2 to 18.

Close call

Health officials in Wisconsin reported 3,496 cases for the first seven months of the year, and Washington state, which has declared an epidemic, has seen more than 3,300 cases of whooping cough. More than 21,000 cases were reported nationwide through August 4, according to the CDC, which is on track to be the largest outbreak in more than 50 years.

In California, the number of reported cases has dropped, likely due to the cyclical nature of the disease, as well as

Source: San Diego County HHSA

increased immunization efforts in adolescents and adults. Only about 460 cases of whooping cough have been reported statewide this year, according to the California Department of Public Health.

Pertussis is a highly contagious respiratory illness that may mimic a cold for the first 10 days. It then can produce a violent and persistent cough with a unique “whooping” sound.

For adults, pertussis may only be a nuisance, like a bad cold. But to infants it can be deadly because they can’t cough up what collects in their lungs and infections can spread.

Vaccinations nearly wiped out whooping cough more than 30 years ago, so the surge in cases in California and around the country has caught health officials off guard.

Among the close calls in California was newborn Matthew Bryce. KPBS and I-Newsource followed this Chula Vista infant as part of their investigation after he was diagnosed with whooping cough in October 2010, two weeks after his birth. Marlon Bryce, a contract specialist at the Naval Medical Center, and his wife, Cindy, couldn’t believe it.

Matthew hadn’t been out of the house much, and their other boys Jordan, then 4, and Joshua, then 3, were up to date on their vaccinations. Marlon had gotten his a month before Matthew was born; Cindy was immunized before leaving the hospital after giving birth.

Tiny Matthew was immediately put on antibiotics, and his parents watched and worried.

Today, at nearly two, Matthew runs with abandon, wrestles with his two older brothers, Jordan and Joshua, and has the marks to prove it.

“I’m just very, very happy he’s here with us today,” said Marlon Bryce during a recent Skyped visit with his family from Germany where he is deployed. “The sad thing is that there are some parents out there today, that, their kids are not here today.”

Need for a new vaccine

Public health officials and scientists agree the existing whooping cough vaccines are still the best tool available to prevent and curb outbreaks. They say children who aren’t immunized against the disease are eight times more likely to contract it than fully immunized children.

“The Tdap vaccine and DTaP vaccine work to a large degree, even with issues with efficacy and issues of waning immunity,” said Dr. Gil Chavez, the deputy director for infectious diseases at the California Department of Public Health. “We have large numbers of people who get vaccinated and are protected for large periods of time.”

State lawmakers passed a bill in 2010 requiring all 7th through 12th graders to receive a Tdap booster before starting school.

Prompted by the numbers of fully immunized people caught up in the outbreaks in California and other states, scientists and health officials have begun to question how much protection the vaccines provide, and for how long.

Source: California Dept. Public Health

Of particular concern was the number of cases in California occurring in fully vaccinated children 7 through 10 years of age. For cases in which immunization history was known, more than 80 percent of the children in that age group diagnosed with pertussis had been fully vaccinated, according to an analysis of state data.

The Marin County study also found vaccinated kids between 8 and 12 years-old to be especially vulnerable at 24 percent effectiveness. Researchers suggested more shots more often might be necessary.

Dr. Mark Sawyer is a pediatric specialist at Rady Children’s Hospital and is a member of the committee that advises the CDC on its immunization schedule. He said the committee is looking at recommending a seventh dose of vaccine.

“We’re seeing waning immunity over time, so it would suggest that we may need more boosters in order to keep elevating the immune system until we come up with a vaccine that has longer protection,” Sawyer said.

Sawyer admits that seventh dose could cause side effects such as swelling or fever – and – the pertussis booster is only FDA approved for a single lifetime dose.

Currently, kids in California receive five doses by the time they are 6 years-old, and another dose — a TDaP booster — between 11 and 12 years of age.

Sanofi Pasteur is one of two pharmaceutical companies that supply pertussis vaccines to the U.S. In an email the company said it has new pertussis vaccines in late-stage clinical trials, some of which are being studied for use in the U.S. Sanofi also maintains that as a class, its pertussis vaccines are 80 to 85 percent effective.

Back in 2010, Matthew’s father Marlon was soft-spoken and thoughtful when he wondered about the pertussis vaccine. “Is it as effective?,” he asked at the time. “I thought that if I did everything I was told to do that our sons would be protected.”

The Bryces are optimistic now about the federal and state health officials’ focus on the disease that sickened their son.

“I’m very happy the CDC is looking into this,” Marlon Bryce said. “I’m happy that Matthew is doing well, that my family, we’re doing well, and I believe it will all lead to good things.”

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