Two waves of the H1N1 virus have already hit the United States, with estimates that as many as 1 in 8 Americans came down with swine flu. Recently, some officials have been pointing to the 1957-58 flu pandemic and wondering if yet another wave of the virus is on the way.

First, a quick history lesson: The influenza pandemic of 1957-58 hit the country with two waves, similar to swine flu in 2009. By late January more than 50 years ago, it appeared that the flu outbreak had ended, just like now.

"The government called the all-clear and then a third wave came along," said Jeff Dimond, spokesman for the Centers for Disease Control. More people died in February and March of 1958 in the third wave than during the first two waves of the pandemic. "You can bet that we aren't anywhere close to issuing the all-clear today," Dimond said.

Another thing scientists and researchers aren't close to doing is predicting a third wave is definitely on the way, Dimond said.

"Flu is completely and totally unpredictable," Dimond said. "We know it comes in waves. We just simply cannot say yea or nay concerning a third wave. As our director has said many times before, 'If you've seen one flu pandemic, you've seen one flu pandemic,'"Dimond said.

Pediatrician Allana Levine in Rockland County, New York said she is worried that too many people have become complacent because swine flu appears on the wane, and is not currently widespread in any state in the country.

"Because we are not seeing as many fatalities these days as we were before, there is less of a panic in the general population," Levine said. "That does concern me."

Levine said she advises all her patients to get the H1N1 vaccine if they haven't already. "While most of my patients who had the flu had mild cases, I have heard of people who have been very, very sick and I don't think people realize how potentially dangerous it is."

Dimond said it's inconceivable to him that any parent would hesitate about getting the vaccination for his or her child. "On the one hand, you don't want to cause any panic, but on the other hand, it is important this population group, especially, be vaccinated."

The statistics make a strong case for vaccination—and continued vigilance. In a normal flu season, about 36,000 people die of flu-related symptoms, according to the CDC. Most are elderly and had underlying health conditions before they got the flu. Out of that 36,000, between 40 and 80 deaths would be pediatric cases, Dimond said. But during the current pandemic, there have been an estimated 1,200 pediatric deaths through the middle of December.

"We have seen that for children who contract this virus, especially if they have underlying health conditions such as asthma or diabetes or multiple sclerosis, it can be extremely dangerous." Between April and mid December, CDC officials estimated there were 55 million total cases of swine flu that led to 246,000 hospitalizations and more than 11,000 deaths.

CDC officials also estimate about 60 million doses of the H1N1 vaccine have already been given out throughout the country. That still leaves millions and millions of people without protection, said Dr. Hank Bernstein, a professor of pediatrics at Dartmouth Medical School and member of the Committee on Infectious Diseases for the American Academy of Pediatrics.

"We also know a majority of people are still susceptible to the pandemic. (If) that third wave comes, a lot of people will be affected."

Dimond, Bernstein and Levine pointed to a number of other reasons for parents to have their children vaccinated for swine flu, if they haven't already.

  • The shots are available. That wasn't the case in the fall and many people were frustrated trying to find a provider who had the shots or having to wait in long lines for the possibility of getting a shot. Dimond said there are 113 million doses in the hands of doctors and officials around the country.
  • There have been few issues with the vaccines. Some people resisted the vaccine citing concern about side effects, but that fear has not been proven. "We know the vaccine is very safe, we've seen no indication of adverse reactions," Dimond said.
  • Vaccinations could affect a possible third wave of H1N1. The reason is simple, Bernstein said. "The more people that are protected, the fewer people that are susceptible, and this really is critically important, because influenza is a vaccine preventable disease."

"You have a vaccine that's safe and potentially can prevent not just significant illness but also mortality," Levine said. "To me it seems crazy not to get the shot."