With the holiday season approaching in the US, doctors are urging people to exercise caution to avoid a surge in common and potentially dangerous winter viruses.

Ms Chow is one of many parents who have had to seek care for an unwell child as winter viruses arrive earlier and with more severity than in recent years - a trend experts say could persist as people gather indoors for the winter holidays.

"We do worry when people start gathering," said Richard Malley, a senior physician with the Division of Infectious Disease at Boston Children's Hospital in Massachusetts.

Symptoms include a cough, congestion, runny nose and fever as well as wheezing in young infants, according to Rachel Orscheln, the director of ambulatory paediatric infectious diseases at St Louis Children's Hospital.

An earlier RSV season followed by more severe flu infections has created a "perfect storm" that is "flooding our paediatric capacity", said Daniel Rauch, the chief of Paediatric Hospital Medicine at Tufts Medicine in Massachusetts.

Some experts said they were not optimistic the issues would resolve soon, as close contact during the the winter holiday season could offer more opportunities for viral transmission.

US infectious disease chief Dr Anthony Fauci said the flu jab was "well matched" to the circulating strain, while White House Covid co-ordinator Dr Ashish Jha urged Americans to "make protecting our loved ones an important part of the conversation we have around the Thanksgiving table".

Taking a rapid test for Covid on the morning of winter holiday celebrations adds another potential layer of protection, Dr Malley said.

"If you're sick, maybe skip the family gathering this year," Dr Rauch said.

Parents and children should also wear masks during travel on planes, trains and other public transportation and could do so during gatherings where they are unsure others are vaccinated, Dr Rauch said.

In the meantime, Amy Knight, the president of the Children's Hospital Association which represents more than 220 hospitals across the US, said paediatric hospitals were "getting creative" and finding extra space for patients while working to keep conditions as normal as possible.