Featured Research

from universities, journals, and other organizations

Leading explanations for whooping cough's resurgence don't stand up to scrutiny

Date:
May 20, 2013
Source:
University of Michigan
Summary:
Whooping cough has exploded in the United States and some other developed countries in recent decades, and many experts suspect ineffective childhood vaccines for the alarming resurgence.

Whooping cough has exploded in the United States and some other developed countries in recent decades, and many experts suspect ineffective childhood vaccines for the alarming resurgence.

Some say the vaccine wears off quicker than public health officials had previously believed. Others suggest that the vaccine protects against illness but does not prevent transmission of the bacterial disease, which is also known as pertussis.

But a University of Michigan-led research team has concluded that neither of these proposed mechanisms for the resurgence of pertussis is supported by the best available evidence. In a study that reviewed 30 years of data from Thailand, they found that vaccines provided long-lived -- possibly lifelong -- protection against the disease and substantially reduced transmission, as well.

"What we found goes against much of what is currently suspected about pertussis resurgence," said U-M population ecologist and epidemiologist Pejman Rohani. "It's not difficult for us epidemiologists to propose some possible mechanism behind the resurgence, but what's been missing so far is an effort to challenge each of these hypotheses to explain the data. That's exactly what we did."

A paper summarizing the team's findings is scheduled for online publication in the Proceedings of the National Academy of Sciences on May 20. The lead author is Julie Blackwood, a postdoctoral research associate in Rohani's lab at the U-M Department of Ecology and Evolutionary Biology.

Thailand was selected as the study site largely because a unique high-resolution dataset of pertussis incidence -- including monthly case notifications from 72 provinces between 1981 and 2000 -- was obtained from that country's Ministry of Public Health. Equally detailed U.S. incidence data are not available from the federal Centers for Disease Control and Prevention, Rohani said.

The researchers expressed several of the leading hypotheses for the resurgence of pertussis in mathematical terms, then used statistical methods to test how well each of these transmission models explained the Thai data. The best fit came from a model that assumed lifelong immunity following either vaccination or naturally acquired infection.

The researchers found no evidence for a pertussis resurgence in Thailand. In fact, their findings highlighted the success of the country's childhood immunization program, pointing to a vaccine-induced increase in "herd immunity," a reduction in the probability of infection that occurs in a population as the number of immune individuals increases.

"We found very few cases overall, and especially in infants," Blackwood said. "So the big underlying finding is that the vaccine is adequately protecting infants from contracting the infection."

The situation with pertussis in Thailand cannot be directly compared with trends in the U.S. for many reasons, including the fact that the two countries use different types of whooping cough vaccine. Thailand mainly uses what's called a whole-cell vaccine, while an acellular vaccine is used in the U.S. In addition, the vaccination schedule in the two countries differs slightly.

Pertussis is a highly infectious respiratory disease that is responsible for nearly 300,000 deaths worldwide annually, primarily among infants in developing countries. In infants, it causes violent, gasping coughing spells.

The U-M-led Thailand study was funded in part by a $1.7 million, five-year National Institutes of Health grant awarded to Rohani and U-M's Aaron King last year. The grant funds efforts to explain the changing patterns of whooping cough outbreaks by using long-term incidence reports from several countries, along with mathematical models of pertussis transmission and statistical methods for extracting information from data.

Funding for the Thailand project was also provided by the U.S. Department of Homeland Security and the Bill and Melinda Gates Vaccine Modeling Initiative. Co-authors of the PNAS paper are Derek A.T. Cummings of Johns Hopkins University, Helene Broutin of the Centre National de la Recherche Scientifique in France and Sopon Iamsirithaworn of Thailand's Ministry of Public Health.

Rohani is a professor of ecology and evolutionary biology, a professor of complex systems and a professor of epidemiology at the U-M School of Public Health.


Story Source:

The above story is based on materials provided by University of Michigan. Note: Materials may be edited for content and length.


Journal Reference:

  1. Julie C. Blackwood, Derek A. T. Cummings, Hιlθne Broutin, Sopon Iamsirithaworn, and Pejman Rohani. Deciphering the impacts of vaccination and immunity on pertussis epidemiology in Thailand. Proceedings of the National Academy of Sciences, 2013; DOI: 10.1073/pnas.1220908110

Cite This Page:

University of Michigan. "Leading explanations for whooping cough's resurgence don't stand up to scrutiny." ScienceDaily. ScienceDaily, 20 May 2013. <www.sciencedaily.com/releases/2013/05/130520154247.htm>.
University of Michigan. (2013, May 20). Leading explanations for whooping cough's resurgence don't stand up to scrutiny. ScienceDaily. Retrieved October 2, 2014 from www.sciencedaily.com/releases/2013/05/130520154247.htm
University of Michigan. "Leading explanations for whooping cough's resurgence don't stand up to scrutiny." ScienceDaily. www.sciencedaily.com/releases/2013/05/130520154247.htm (accessed October 2, 2014).

Share This



More Health & Medicine News

Thursday, October 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Pregnancy Spacing Could Have Big Impact On Autism Risks

Pregnancy Spacing Could Have Big Impact On Autism Risks

Newsy (Oct. 1, 2014) — A new study says children born less than one year and more than five years after a sibling can have an increased risk for autism. Video provided by Newsy
Powered by NewsLook.com
Robotic Hair Restoration

Robotic Hair Restoration

Ivanhoe (Oct. 1, 2014) — A new robotic procedure is changing the way we transplant hair. The ARTAS robot leaves no linear scarring and provides more natural results. Video provided by Ivanhoe
Powered by NewsLook.com
Insertable Cardiac Monitor

Insertable Cardiac Monitor

Ivanhoe (Oct. 1, 2014) — A heart monitor the size of a paperclip that can save your life. The “Reveal Linq” allows a doctor to monitor patients with A-Fib on a continuous basis for up to 3 years! Video provided by Ivanhoe
Powered by NewsLook.com
Attacking Superbugs

Attacking Superbugs

Ivanhoe (Oct. 1, 2014) — Two weapons hospitals can use to attack superbugs. Scientists in Ireland created a new gel resistant to superbugs, and a robot that can disinfect a room in minutes. Video provided by Ivanhoe
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins