Nav: Home

Using satellite images to better target vaccination

October 06, 2016

Satellite images that capture short-term changes in population size in communities in the developing world can help vaccination campaigns achieve more complete coverage to help prevent and control disease outbreaks. A team of researchers led by Penn State scientists have combined satellite imagery, vaccination records, and measles case reports to illustrate how using predictable population fluctuations can help to improve vaccination coverage -- a vital factor in combatting infectious disease outbreaks. The research is published in the October 5, 2016 edition of the journal Scientific Reports.

"Access to vaccinations, and other preventative health services, is limited in much of the developing world," said Nita Bharti, assistant professor of biology at Penn State and an author of the paper. "We've shown, however, that access to vaccines isn't static through time. The same seasonal gatherings of people that we've previously shown to correlate with times of disease transmission risk could also be used to better target public health interventions -- taking advantage of times of high population density to more efficiently distribute care."

The researchers studied a measles outbreak in Niamey, Niger that resulted in over 10,000 cases and nearly 400 deaths in 2003 and 2004. Population estimates available at the time of a vaccination campaign to combat the outbreak did not take into account seasonal migrations into Niamey. This missing information led to an underestimate of the population in Niamey and therefore an overestimate of the proportion of children vaccinated during the campaign. The team used satellite images of nighttime lights in Niamey to more accurately estimate the size of the population at the time of the outbreak and estimate the percentage of the population that received the vaccination. The team's retrospective estimates much more closely matched actual measurements of the coverage of the vaccination campaign that were made following the outbreak.

"Lots of recent work has been done on remote measures of human movement," said Bharti. "Satellites are actually a pretty old technology compared to cell phones and social media. But satellite-based measures are really appealing, because we can look back in time and assess trends in patterns of human movement and distribution. Cell phones are an exciting new technology and have great potential for public health outreach, but the rapid rate of adoption means that we need to be careful about interpreting trends -- the patterns might reveal changes in behavior, or they might just reflect trends in accessibility to phones."

The researchers further constructed a computer model based on population estimates from satellite images, vaccination records, and measles case studies to simulate measles outbreaks and evaluate the effectiveness of vaccination strategies. Their models showed that in a reactive vaccination campaign -- one that tries to control an ongoing outbreak -- early intervention was the most effective, regardless of fluctuating population size. The model also showed that the coverage and reach of a preventative vaccination campaign -- one that tries to prevent outbreaks before they start -- could be improved by timing the campaigns with peaks in population size.

"Human movement and gathering have been a big part of understanding the epidemiology of directly transmissible diseases, like measles," said Matthew Ferrari, associate professor of biology and statistics at Penn State and an author of the paper. "What was exciting about this project was to turn that phenomenon into a potential solution. Rather than looking at times of large gatherings -- harvest season, or cultural festivals -- as high risk periods, we can look at them as opportunities to serve people who are normally beyond the reach of conventional health systems."

The researchers also showed that estimates of population fluctuations based on satellite images of nighttime lights in two other cities in Niger, Maradi and Zinder, could be used to coordinate vaccination campaigns and other public health interventions even when detailed vaccination records or disease case studies are not available. With the satellite data, the effectiveness of vaccination campaigns can be maximized by coordinating with predictable seasonal peaks in population size in the cities, expanding the reach of the campaign to many people who might otherwise have been missed.

"There's a lot of discussion about the difficulty of reaching the 'last mile,' those people who are well beyond the reach of the conventional health system," said Ferrari. "But if we recognize that the 'last mile' is a moving target because populations are constantly in flux, then we can target efforts in ways to make more efficient use of limited public health resources. Remote measures, like satellite imagery, allow us to make pretty rapid assessment of regular movements that could lead to better targeting -- it doesn't replace 'boots on the ground' evaluation, but it could go a long way to helping to prioritize efforts."
-end-
In addition to Bharti and Ferrari, the research team includes Bryan T. Grenfell from Princeton University and the Fogarty International Center of the National Institutes of Health, Ali Djibo of the Université de Niamey in Niger, and Andrew J. Tatem of the Fogarty International Center, the University of Southampton in the United Kingdom, and the Flowminder Foundation in Stockholm, Sweden.

The research was supported by Branco Weiss - the Society in Science, the Bill and Melinda Gates Foundation, the Penn State Huck Institutes of the Life Sciences, the Research and Policy for Infectious Disease Dynamics (RAPIDD) program of the Science and Technology Directorate of the U.S. Department of Homeland Security, the Fogarty International Center, the U.S. National Institutes of Health, and the Wellcome Trust.Matthew Ferrari: mferrari@psu.edu, +1 (814) 865-6080

Nita Bharti: nita@psu.edu (unreachable in the field until after November 1, 2016)

IMAGES

Two images with captions and credits are available for download at https://psu.box.com/v/Bharti10-2016 (If captions are not visible, click the horizontal arrow in the small right-most box at the top of the page.)

TITLE OF RESEARCH PAPER

The title of the research paper that will be published in the Nature Publishing Group journal Scientific Reports is "Measuring populations to improve vaccination coverage."

Penn State

Related Vaccination Articles:

Researchers develop microneedle patch for flu vaccination
A National Institutes of Health-funded study led by a team at the Georgia Institute of Technology and Emory University has shown that an influenza vaccine can produce robust immune responses and be administered safely with an experimental patch of dissolving microneedles.
Rotavirus vaccination in infants and young children
Rotaviruses (RV) are the commonest cause of diarrhea in infants and young children worldwide.
Industry and occupation affect flu vaccination coverage
Not surprisingly, healthcare workers are almost twice as likely to get flu vaccines as those in other occupations.
Child's vaccination data handily available via Kasvuseula service
Parents can now follow their tots' vaccinations via the Kasvuseula online service, which provides analytical data on the child's growth.
Foot-and-mouth crises to be averted with vaccination strategy
Future outbreaks of foot-and-mouth disease (FMD) can be controlled effectively and quickly with vaccinations -- saving millions of pounds and hundreds of thousands of livestock -- according to research by the University of Warwick.
HPV prevalence rates among US men, vaccination coverage
Human papillomavirus (HPV) infection is the most common sexually transmitted infection in the United States, as well as a cause of various cancers, and a new study published online by JAMA Oncology estimates the overall prevalence of genital HPV infection in men ages 18 to 59.
Anesthetic cream best for relieving vaccination pain in infants
For babies under age one year, lidocaine cream, combined with a small amount of sugar given by mouth and infant soothing, can help relieve pain from routine vaccinations, according to a study in Canadian Medical Association Journal.
Measles prevention -- how to pull the trigger for vaccination campaigns?
Routine vaccination has greatly reduced measles deaths in recent years, but very high vaccination coverage is needed to prevent disease outbreaks.
Using satellite images to better target vaccination
Vaccination campaigns can improve prevention and control of disease of outbreaks in the developing world by using satellite images to capture short-term changes in population size.
Maternal vaccination again influenza associated with protection for infants
How long does the protection from a mother's immunization against influenza during pregnancy last for infants after they are born?

Related Vaccination Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...