Pregnant women, young children and people with chronic medical conditions are among those considered at greatest risk of having complications after becoming infected with the 2009 H1N1 influenza A virus, infectious disease expert Michael Cooperstock said Oct. 29 at a noon Lunch and Learn presentation sponsored by University Health System.
This high-risk group should be “top priority for getting the limited supply of novel H1N1 flu vaccine, along with persons in contact with an infant under 6 months of age and health care workers in contact with people who have these risk conditions,” said Cooperstock, professor of child health. “People who are close contacts of any of the risk groups, such as family members and health care workers, will be the next priority as additional H1N1 vaccine becomes available.”
Novel H1N1 flu, originally called swine flu, first surfaced in early 2009 in Mexico and quickly spread throughout the United States since it arrived here in April. By early summer, the virus had spread to so many countries, the World Health Organization deemed it a flu pandemic.
“This action reflects the spread of the virus and does not refer to the severity of illness caused by the virus, which appears not to be more severe than ordinary seasonal influenza,” Cooperstock said.
Swine flu is a human disease, he said. People get it from other people, not from handling or eating pork, even though it contains genes from flu viruses found in swine as well as genes from bird and human flu viruses.
Unlike seasonal influenza, 2009 H1N1 is “a new or mutated strain of influenza virus to which the human population has little or no pre-existing immunity, giving pandemic potential,” Cooperstock said.
Symptoms of H1N1 influenza, like regular flu symptoms, include fever, cough, sore throat, runny nose, body aches, headache, chills and fatigue. It may cause vomiting and diarrhea in some people. “Currently, available lab tests are not fully sensitive to this virus, so the decision to treat the flu must be based primarily on the symptoms,” Cooperstock said. “Only lab tests can confirm whether a person has the H1N1 virus.”
So far, there have been hardly any cases of seasonal flu this year, he said. “Almost all of the viruses identified lately have been the 2009 H1N1 virus. A piece of good news about this virus is that most adults over age 65 have some previous immunity and are spared the infection more than 90 percent of the time. This age group usually has the most hospitalizations and deaths from flu.”
The 2009 H1N1 flu virus spreads in much the same way as the seasonal flu virus spreads, mainly from person-to-person through coughing or sneezing, Cooperstock said. Sometimes people may become infected by touching something — such as a surface or object — with flu viruses on it and then touching their mouths, noses or eyes.
Illness with the 2009 H1N1 virus has ranged from mild to severe, he said. “Even though most people who have been sick have recovered within a couple of days without needing medical treatment, hospitalizations and deaths from infection with this virus have occurred.”
The Centers for Disease Control and Prevention recommends that people with influenza-like illness remain at home except when necessary to seek required medical care, he said. They should remain at home until they have been free of fever exceeding 100°F [37.8°C] for at least 24 hours without the use of fever-reducing medications.
Cooperstock said that by taking precautionary measures such as getting vaccinated, washing hands, covering one’s cough, staying home from work or school if sick, and standing 3 feet to 6 feet away from an infected person can help prevent the spread of infection to others while protecting yourself, too.
Flu vaccines are the best protection against both seasonal flu and 2009 H1N1 flu, Cooperstock said. The new H1N1 strain requires a separate vaccine. He advises people to get in touch with their health care providers and local and state health departments to learn when and where the novel H1N1 vaccines will be available. “The more people know about planning and prevention, the more they can be ready if an emergency happens,” Cooperstock said.
At Mizzou, there are plans for handling pandemic flu and for keeping students, faculty and staff informed (see MU Alert). With questions about seasonal and the new H1N1 influenza viruses, e-mail cooperstockm@health.missouri.edu.