Whooping Cough Vaccine Won't Prohibit Contagiousness ; Health Agencies Attempt New Strategies

Last fall, government research suggested that while the whooping cough vaccine may keep people from getting sick, it won't necessarily stop them from spreading the disease. Whooping cough, or pertussis, is a highly contagious disease and cases of it are on the rise. In 2012, the CDC received reports of more than 48,000 whooping cough cases, including 18 deaths after whooping cough infection. Health officials needed to know what was causing the outbreaks.

The public got a new vaccine for whooping cough in the 1990's. Previously, kids were given the whole-cell pertussis vaccine, but for better safety, the U.S. switched to the acelluar pertussis vaccines, according to the American Academy of Pediatrics. The Academy reported that researchers found that during a 2009 and 2010 whooping cough outbreak, teenagers who received the newer acellular vaccine had a six times higher risk of contracting whooping cough due to "waning immunity" compared to those who had been given the whole-cell vaccine. Additional boosters for whooping cough were added to the schedule.

The government study that was published last fall explained that baboons in their experiment who had been vaccinated with the current vaccine didn't get sick after being exposed to whooping cough, but they had high levels of the pertussis bacteria in their respiratory system for five weeks. The authors of the government study said these baboons were contagious for five weeks after being exposed to pertussis. Baboons who were vaccinated with the old vaccine before being exposed to whooping cough had very low levels for only two weeks, according to NBC. "It could explain the increase in pertussis that we're seeing in the U.S.," Tod Merkel, an FDA researcher, said of the disappointing findings. According to Science News, poorer countries have maintained low infection rates by sticking with the older vaccine.

This week, Science News reported that even more bad news was discovered about the acellular pertussis vaccines. Whooping cough attacks with varied key compounds. One type, coined "adhesins," help it stick to vulnerable tissue. Unfortunately, the adhesins' genetic "instructions" have begun to change which might make the vaccine even less effective. Whooping cough, according to Science News, is believed to have also changed genetically so that it has greater pertussis toxin. Researchers in the Netherlands, according to Science News, suggested that use of the acellular vaccine may have encouraged these changes. Wall Street Journal 's Market Watch reported today that Synthetic Biologics is developing a treatment to target and neutralize the pertussis toxin in order to help prevent whooping cough from being as serious in infected infants.

Additional avenues are being explored for fighting whooping cough outbreaks. The whole-cell vaccine is still used in more than half the world, but according to Science News, it's unlikely the U.S. will go back to the old whooping cough vaccine. Researchers are trying to improve the current vaccine. Additionally, a few weeks ago, Meridian Bioscience got approval for a speedy whooping cough detection test. Its nasal swab test can show results in one hour. Current tests can take a week or more to give a proper diagnosis, according to a Gannett affiliate.

Also, according to Newsday, health officials are keeping their eye on social media platforms like Twitter after the small business Sickweather detected a whooping cough outbreak using algorithms to scan Twitter and Facebook postings about two weeks before local health officials issued their warning. "That's the Holy Grail," Mark Dredze, of Johns Hopkins University in Baltimore, said. Dredze is also a Sickweather adviser. "We'd love these systems to tell us there's a brand new disease and it's going to be a big thing."

Earlier today, Infection Control Today announced new findings that might help lead to a vaccine that will work better, because "strategies used to date have not completely eradicated strains of the bacteria, instead leading to an increase in diversity." Genomic analysis conducted at the Wellcome Trust Sanger Institute of over three hundred strains of the whooping cough bacteria that has been collected over the last 100 years is helping researchers see how vaccines have shaped whooping cough's evolution, according to Infection Control Today. Dr. Simon Harris, an author of the study, said that by seeing how it escapes vaccines, researchers will be able to develop better strategies to control and eradicate whooping cough in the future.

[Photo by James Gathany]