Md. health officials track flu with e-mail queries

The Baltimore Sun

You're all achy, coughing and feverish. Work is out of the question, but you're not sick enough to see a doctor. How nice it would be if someone checked in to ask how you're feeling.

The Maryland Department of Health and Mental Hygiene won't send over a pot of chicken soup. But state epidemiologists have a first-in-the-nation, Web-based project to ask thousands of residents whether they've been laid low by flu symptoms.

The Maryland Resident Influenza Tracking Survey is designed to augment reports from the doctors, hospitals and medical laboratories traditionally used to gather data on the geography and intensity of the flu season. The health department sends a weekly e-mail to people who sign up, asking them such questions as whether they've had a fever or a sore throat.

"We're looking at ways to fill in the gaps of our existing surveillance system," said Rene Najera, an epidemiologist at the health department. "We're trying to get at people who don't go to the hospital or do not see physicians. When those people do not seek care, they don't get reported to us."

With a more complete picture of a spreading flu epidemic, health officials say, they might be more effective with efforts to vaccinate people and teach them how to avoid catching and spreading the flu.

Each winter, 5 percent to 20 percent of the U.S. population gets the flu, according to the federal Centers for Disease Control and Prevention. More than 200,000 are hospitalized, on average, and 36,000 die from flu complications. Older people, young children and those with chronic conditions or weakened immune systems are especially vulnerable.

Maryland's new tracking survey began Oct. 5, checking on a growing list of Marylanders. More than 350 have signed up so far for the weekly e-mails. And so far, they're feeling pretty good, Najera said.

Of the 220 people who responded to the most recent questionnaire, only two reported experiencing flu-like symptoms during the week, very close to the 1 percent reported by the "sentinel" physicians who share office statistics with the health department.

"It's been that way for the last four weeks," Najera said. But reports from the two sources are "both trending upward."

That's as expected. The 2008-2009 flu season is just getting under way. Maryland health authorities reported the state's first laboratory-confirmed flu case Monday. Tests confirmed that a Type A (H1) flu virus sickened a child in the Baltimore area.

Until now, public health authorities have relied mainly on a few dozen physicians, medical labs, hospitals and other health care institutions to report regularly on the illnesses they are seeing.

DHMH epidemiologists also investigate and track outbreaks of flu and pneumonia in schools, nursing homes and other institutions.

Last year, the state confirmed 4,029 cases of seasonal flu, peaking in the second week of February. But that is only a fraction of the actual case volume, missing the people who never seek professional care.

Seeking a larger sample and a more comprehensive yardstick, Najera came across FluTracking.net, a program used in Australia during the past two Southern-Hemisphere flu seasons to find more flu cases via the Internet.

So he adapted it for Maryland. "I believe we're the first in the nation" to use it, he said.

People who sign up online provide their birth date, county of residence, ZIP code and e-mail address. They report whether they've had a flu vaccination and whether they work in a health care setting.

Then, once a week during flu season, they receive an e-mail reminder to log on to the survey's Web site.

There, they're asked whether they experienced a fever, cough or sore throat during the previous week. If so, they're asked whether the illness caused them to miss work, school or other normal activities, a rough measure of severity.

Participants are also asked whether they've received their flu vaccination within the prior week - "a chance to tell us if that's changed," Najera said.

The survey is short, and it does not gather enough information to confirm that the participant has the flu, he said. But the symptoms - fever, cough or sore throat - are the same ones the traditional sentinels report to the health department.

While the questions might pick up some nonflu illnesses, such as strep throat and any number of upper respiratory viruses, they will surely catch influenza cases, too.

"The reasoning is that, during the flu season, the great majority of people with those specific symptoms, more often than not, will have the flu and not similar infections," Najera said. "We call it sensitive, but not specific."

Data on when the flu arrives and where and how it is spreading will be shared weekly with local health departments, health care providers and medical laboratories, helping them to plan their responses.

It's not a perfect sampling, Najera said. For example, it misses Marylanders who do not use computers or who lack access to the Internet.

But the more people who take part, the more reliable the data will be. Australia, a nation of 21 million, enrolled 3,600 people in its surveys. Maryland, with a population of 6 million, is hoping for 2,000.

Howard County health officer Dr. Peter L. Beilenson called the effort "interesting ... modestly useful and it's free." But he cautioned that participants are self-selected and might not be representative of the population at large, including particularly vulnerable groups such as day care providers and people with suppressed immune systems.

"What would we be doing differently with that information?" he asked. "We can always do better, but our main purpose is getting as many people vaccinated as possible, and educating people on how to prevent the spread of the flu."

The Maryland flu tracking survey is just one Internet-based alternative for public health authorities seeking to monitor flu activity. Another is Google search tracking.

When people get sick, the online search engine provider has found, many of them run Internet searches on their symptoms. And Google says the volume of searches on key flu-related terms closely mirrors the volume of flu cases reported by traditional means to CDC.

"By counting how often we see these search queries, we can estimate how much flu is circulating in various regions of the United States," says the company Web site. You can track flu-related queries, state-by-state, at www.google.org/flutrends/.

Nationally, seasonal influenza remains at a "low" level, according to the latest CDC report, for the week ending Nov. 8. It notes "sporadic" activity in 15 states, "local" activity in one state and no activity in the rest.

The CDC has had no reports of pediatric deaths so far this season. The count of adult deaths related to pneumonia and influenza was below the "epidemic" threshold. So far, the Type A flu viruses have dominated the lab results, outnumbering the Type B strains by a margin of 4-to-1.

Maryland health officials continue to urge residents to get vaccinated.

Noting the flu-like illnesses and gastroenteritis that spread through crowds gathered for a papal visit to Australia last summer, they said they expect a similar pattern among the more than 1 million people expected to crowd Washington for the presidential inauguration Jan. 20.

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