Featured Research

from universities, journals, and other organizations

Contact among age groups key to understanding whooping cough spread and control

Date:
November 11, 2010
Source:
University of Michigan
Summary:
Strategies for preventing the spread of whooping cough -- on the rise in the United State -- should take into account how often people in different age groups interact, research suggests.

Strategies for preventing the spread of whooping cough -- on the rise in the United States and several other countries in recent years -- should take into account how often people in different age groups interact, research at the University of Michigan suggests.

The findings appear in the Nov. 12 issue of the journal Science.

Thanks to widespread childhood vaccination, whooping cough (pertussis) once seemed to be under control. But the illness, which in infants causes violent, gasping coughing spells, has made a comeback in some developed countries since the 1980s, becoming a major public health concern. In addition, there's been a shift in who's getting sick, with fewer cases seen in preschool children and more in teenagers, but the reasons for the changing patterns have been unclear.

A variety of explanations have been proposed -- genetic changes in the bacterium that causes the disease or the "wearing off" of immunity in people who were vaccinated years ago, for example.

But by combining two independent sets of data from previous studies, epidemiologists Pejman Rohani, Xue Zhong and Aaron King found that age-specific contact patterns alone can explain the observed shifts in prevalence and age-specific incidence.

One set of data came from an unplanned "natural experiment." In Sweden, where infants had been routinely vaccinated for nearly 30 years, concerns about vaccine safety and efficacy led to a halt in pertussis vaccination in 1979. Immunization resumed in 1996 using a different vaccine. During the hiatus and after vaccination resumed, the Swedish Institute for Infectious Disease Control collected data on whooping cough incidence by age group.

The second data set was from a 2008 study in which more than 7,000 people from eight European countries kept track of all the contacts they had with other people during one day, recording the age and sex of the person they interacted with, where the interaction took place and the duration and type of contact (such as conversation or physical contact). A key finding of that study was that children interacted far more frequently with other children than with adults.

The U-M researchers developed a simple mathematical model of whooping cough transmission that incorporated the contact data and then compared the model's predictions with the actual incidence data. The model accurately predicted the declines in whooping cough cases seen in Swedish infants, toddlers and adults and the upturn in cases among teenagers with the resumption of vaccination.

The results cast doubt on the prevalent notion that infected adults, in whom the illness often goes undiagnosed, act as a reservoir for the disease and are a major source of transmission to younger folk. In many countries, concerns about this possibility have prompted adult booster vaccination programs.

But the U-M study shows that, overall, "the role of adults in transmission is minimal," and that blanket booster-vaccination of adults is unlikely to be an efficient strategy for controlling the disease, said King, an assistant professor of ecology and evolutionary biology with a joint appointment in mathematics.

The researchers stressed that because the study used incidence data from Sweden, one can only speculate on how its results apply to the United States, where infant vaccination compliance rates are lower and the population is much more diverse. "We need similar analyses for the United States," said Rohani, a professor of ecology and evolutionary biology with a joint appointment in the Center for the Study of Complex Systems.

The study makes two robust conclusions, said King. "The first point is that we see strong evidence for the efficacy of vaccination directed at children when compliance is high. The second is that better knowledge of actual contact patterns among age groups is crucial for the design of more effective and economical vaccination strategies."

The researchers received funding from the Department of Homeland Security, the Fogarty International Center (National Institutes of Health) and the Bill & Melinda Gates Foundation.


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. Pejman Rohani, Xue Zhong, and Aaron A. King. Contact Network Structure Explains the Changing Epidemiology of Pertussis. Science, 12 November 2010 330: 982-985 DOI: 10.1126/science.1194134

Cite This Page:

University of Michigan. "Contact among age groups key to understanding whooping cough spread and control." ScienceDaily. ScienceDaily, 11 November 2010. <www.sciencedaily.com/releases/2010/11/101111141818.htm>.
University of Michigan. (2010, November 11). Contact among age groups key to understanding whooping cough spread and control. ScienceDaily. Retrieved July 22, 2014 from www.sciencedaily.com/releases/2010/11/101111141818.htm
University of Michigan. "Contact among age groups key to understanding whooping cough spread and control." ScienceDaily. www.sciencedaily.com/releases/2010/11/101111141818.htm (accessed July 22, 2014).

Share This




More Health & Medicine News

Tuesday, July 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

TheStreet (July 21, 2014) New research shows Gilead Science's drug Sovaldi helps in curing hepatitis C in those who suffer from HIV. In a medical study, the combination of Gilead's Hep C drug with anti-viral drug Ribavirin cured 76% of HIV-positive patients suffering from the most common hepatitis C strain. Hepatitis C and related complications have been a top cause of death in HIV-positive patients. Typical medication used to treat the disease, including interferon proteins, tended to react badly with HIV drugs. However, Sovaldi's %1,000-a-pill price tag could limit the number of patients able to access the treatment. TheStreet's Keris Lahiff reports from New York. Video provided by TheStreet
Powered by NewsLook.com
$23.6 Billion Awarded To Widow In Smoking Lawsuit

$23.6 Billion Awarded To Widow In Smoking Lawsuit

Newsy (July 20, 2014) Cynthia Robinson claims R.J. Reynolds Tobacco Company hid the health and addiction risks of its products, leading to the death of her husband in 1996. Video provided by Newsy
Powered by NewsLook.com
Tooth Plaque Provides Insight Into Diets Of Ancient People

Tooth Plaque Provides Insight Into Diets Of Ancient People

Newsy (July 19, 2014) Research on plaque from ancient teeth shows that our prehistoric ancestor's had a detailed understanding of plants long before developing agriculture. Video provided by Newsy
Powered by NewsLook.com
Contaminated Water Kills 3 Babies in South African Town

Contaminated Water Kills 3 Babies in South African Town

AFP (July 18, 2014) Contaminated water in South Africa's northwestern town of Bloemhof kills three babies and hospitalises over 500 people. The incident highlights growing fears over water safety in South Africa. Duration: 02:22 Video provided by AFP
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:
from the past week

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