Doctors are encouraging people to take steps to protect themselves as millions of Americans prepare for holiday gatherings this week. This comes as data from the past two days shows a sharp increase in flu and COVID-19 cases, creating the perfect storm for indoor events.

'Tis the season for holiday parties, air travel, and respiratory viruses.

"Germs like the gatherings indoors in order to spread," said Dr. Carla Garcia Carreno, Children's Health Plano Infection Prevention Director.

Children's Health reports a 175% increase in flu cases and a 61% increase in RSV cases during the week of Dec. 14.

The U.S. Centers for Disease Control and Prevention estimates 4.6 million flu cases across the United States since the season began, and 1,900 patients have died.

Carreno said people who are traveling at airports should take special care to stay safe.

"Try to avoid public transportation because this is a perfect environment where germs can spread," Carreno said. "People who are especially vulnerable should wear a mask."

Carreno said try to maintain distance in public places to prevent getting sick.

"Everything that we learn with COVID goes, such as hand washing, not sharing utensils, coughs and sneezing etiquette. If you're going to cough and sneeze, do it in your elbow or with a tissue and then immediately hand washing afterwards," Carreno said.

She also encourages people to get vaccinated.

"We have our flu shots that are recommended for everybody six months and older. We have an RSV vaccine that is recommended for older people, pregnant women, and especially to protect the young infant."

The doctor said try to avoid holiday gatherings if you're sick.

"If you have a vulnerable person, like a small baby that is too young to be vaccinated or somebody whose immune system is weakened by, any resistance medications or cancer, those people should probably not gather in order to prevent this exposure," Carreno said.

Don't delay going to the doctor if you do get sick.

"There are certain red flags in order for parents to know we need to seek medical care immediately," Carreno said. "Those are if they have any signs of dehydration or if they have any difficulty breathing."

Mountain cedar is causing symptoms for many North Texans. The doctor said allergies are different from respiratory viruses because they typically don't cause fever or fatigue.