While many people are using mass transit systems to get to their Thanksgiving celebrations, doctors are reminding people to keep healthy and avoid getting sick.

While the number of swine flu cases has been on the decline, Dr. William Mercer of the Wheeling-Ohio County Health Department said people need to take even more precautions.

He said this is the time of year when there could be an increase in H1N1 cases as more people gather together at homes and the population mixes at places like airports.

Mercer said to follow the same precautions as when the swine flu pandemic first started: wash hand properly and use hand sanitizers.

He said a person is not likely to catch the swine flu or other illnesses by sitting next to someone who is sick. The risk is when a person coughs or sneezes into their hands then touches a surface, leaving germs behind that can live for up to three hours.

"If you do have a fever and you're not well, I would not get on that plane or the bus. Again, that's going to be hard -- people have plans, reservations -- but you know you're probably contaminating a lot of people," Mercer said.

With regard to masks, Mercer said, "Say if you are the one who is sick and who is coughing, you would maybe want to ask for a mask. But if you're not sick, wearing a mask really probably does not help that much."

Heath officials have estimated that about half of the U.S. population will contract the swine flu. Mercer said he recommends everyone receive the H1N1 vaccine as it becomes available. In the meantime, he said common sense and good hygiene will help protect people from the virus.

For more information, including information about local vaccination clinics, visit our special H1N1 question-and-answer section.