When swine flu emerged from Mexico in April, it spurred alarming reports of severe illness, hospitalizations and deaths.
In the months since, public health officials have stressed the illness is no more serious for most people than a seasonal flu.
But they have also discovered some important distinctions between the two illnesses: the age groups that are most susceptible to swine flu, the way the virus proceeds through the body, and the possibility that a person could have the illness without a fever.
People deciding whether to take the swine flu vaccine — which is expected to start arriving in Georgia as early as Tuesday — may want to consider these differences.
“I would not call this a benign virus. People are winding up in ICUs,” said Dr. Richard Wenzel, past president of the International Society for Infectious Diseases.
Federal officials said Thursday that Georgia is among 25 states and cities that have placed orders for swine flu vaccine, and the first doses could be administered as early as Tuesday.
For the great majority of people who catch the swine flu, experts say the symptoms will resemble those of seasonal flu — coughing, sneezing, body aches and fever. While people need to monitor the illness, they don’t need to rush to the emergency room.
In contrast to the seasonal flu that poses the greatest risk for older adults, the swine flu is largely targeting, hospitalizing and in some cases even killing those between 5 and 24 years of age, experts note.
In addition, the virus also has the capacity to infect lung tissue differently than the common flu, striking deeper areas that are vital to supplying oxygen to the blood. That could make people more susceptible to lung infections such as pneumonia, experts say.
Swine flu is also hitting pregnant women harder than the seasonal flu.
Swine flu, also known as H1N1, is widespread in Georgia, where 432 people have been hospitalized and 21 have died, according to state officials.
Health officials say they expect the vaccine to start arriving in Georgia next week, with 2 million doses coming by the end of this month. The first shipment will be 54,000 doses of nasal mist vaccine, which will be prioritized for children, officials said.
The experts’ primary concern are the children and young adults, as they account for a high percentage of the cases. Cases are relatively rare among those 55 and older, the group typically hard hit by the seasonal flu.
“The overall death rate is comparable to the seasonal flu, but the people who are dying are younger,” said Dr. James Steinberg, a professor of infectious disease at the Emory University School of Medicine. Each year about 36,000 Americans die of the seasonal flu.
Swine flu outbreaks have happened before, but this virus, known as novel 2009 H1N1, is a new strain. While researchers continue to study it, some experts suspect it may contain properties of earlier flu viruses that have appeared through the years. That may account for some partial immunity among older people and why young people appear more vulnerable, Steinberg said.
That reasoning may also explain why the illness has spread among schoolchildren and college students more quickly than the regular flu.
In that population, “it is more contagious,” said Wenzel, who is a professor and chairman of the department of internal medicine at Virginia Commonwealth University. “We have a huge susceptible population.”
Swine flu doesn’t travel any differently than common flu. This much is true for both: You can catch it just by talking to an infected person, even if he or she doesn’t sneeze on you, he said.
People are contagious about as long as if they had regular flu, Wenzel said. For adults, that’s about five to seven days with the regular flu, and a day or so more for those with swine flu, he said. Children can continue to pass on the virus for up to three weeks with both bugs, he said.
Children top the government’s priority list for swine flu shots this year. Typically, the flu season has 50 to 70 pediatric deaths nationally. But since swine flu appeared in April, there have already been about 50 pediatric deaths, even before the flu season hits in earnest, according to the Atlanta-based Centers for Disease Control and Prevention.
“The numbers are worrisome,” said Dr. Dan Jernigan, deputy director of the CDC’s influenza division.
Federal health officials have also prioritized pregnant women, health care workers, people who live or care for children under 6 months of age, and people ages 24 to 64 who have chronic health problems.
Flu is generally a respiratory illness. But some experts also say the swine flu virus is finding its way more often into people’s gastrointestinal tract, and even into human waste. It’s appearance in human waste raises concerns about a greater chance of it spreading, especially in hospitals, Wenzel said.
Wenzel, who has studied swine flu in several South American countries, said the illness sometimes produces no fever. That’s a concern, he said, because recent federal guidelines on swine flu say infected children should stay at home until 24 hours after they no longer have a fever.
The CDC has recommended that everyone who can should get the swine flu vaccine. But a recent Consumer Reports poll showed that a majority of U.S. adults say they are either reluctant or unsure about whether they or their children will get vaccinated for the virus.
CDC officials say the swine vaccine’s side effects are expected to be minor and may include redness and swelling at the site of injection. In a few cases, one might develop a low-grade fever and minor aches, officials said.
The seasonal flu vaccine does not provide protection from the swine flu. People can receive the swine flu injection on the same visit as they obtain the seasonal flu shot, but they would probably want to get them in separate arms, experts say.
People should not get the seasonal flu nasal mist vaccine and the swine flu mist vaccine at the same time, as both are weakened live viruses, the CDC said. The nasal spray can be administered to people age 2 through 49 who do not have chronic medical conditions and are not pregnant.
For young and middle-age healthy people, the swine flu vaccine is expected to offer about 70 percent to 90 percent protection from the virus, the CDC said.
With the shot, Wenzel said, “the odds are you’re not going to get it.”
Health officials are recommending that everyone who can take the vaccine get the seasonal flu shot, which is already available, and take the swine flu vaccine when it arrives.
One dose of the vaccine is all that’s needed to protect adults (age 10 and up) and can spark protection within 10 days of the shot.
Children younger than 10 require two doses about three weeks apart.
Infants younger than 6 months old are too young for either the swine flu or the seasonal flu vaccine. Therefore, people who live with or care for them should consider getting vaccinated.
The 2009 swine flu vaccine is different from the 1976 vaccine. Anyone who received a vaccine in 1976 will need to be vaccinated again.
Source: The Centers for Disease Control and Prevention