Influenza took a holiday last year and left us alone while we struggled with the COVID-19 pandemic, but health experts say don’t count on being so lucky this time around and urge everyone to get the flu vaccine.

This fall, that pitch comes amid the campaign for everyone to get the COVID-19 vaccine — and for many a booster — too. Soon, school kids under age 12 may become eligible for the COVID-19 shot as well.

So if you need a COVID-19 jab and haven’t yet had the flu shot this year, should you go for the twofer and get both at the same time?

Among public health officials and medical experts, there isn’t much doubt.

“Yes,” said Dr. Monika Roy, Santa Clara County assistant health officer and communicable disease controller. “Flu and COVID vaccines can be administered at the same time. Everyone should go and get a flu shot, and everyone eligible for a COVID vaccine should get one as well.”

Contra Costa County Health Officer Dr. Chris Farnitano said federal health authorities had initially advised that the COVID-19 vaccines be given by themselves “out of an abundance of caution.”

“That was mostly to better understand common side effects,” Farnitano said. “But now that we’ve had a lot of experience and we have a good sense of the common side effects of the COVID-19 vaccines, there’s no reason to space them out any more.”

One bit of advice, though: Get the shots in separate arms.

The U.S. Centers for Disease Control and Prevention now advises that “COVID-19 vaccines may be administered without regard to timing of other vaccines,” though it says “if multiple vaccines are administered at a single visit, administer each injection in a different injection site.” If combined with other vaccines that “may be more likely to cause a local reaction,” it says they should be given “in different limbs, if possible.”

Dr. Darvin Scott Smith, chief of infectious disease at Kaiser Permanente in Redwood City, said Kaiser protocols call for giving the COVID-19 vaccine in the “non-dominant” arm — the left on a right-hander — and the flu shot, which typically produces a milder reaction, in the other.

Kaiser, like many health providers, recommends those who are eligible get both shots together.

“There is no advantage in doing them separate,” Smith said. “It’s a bit more inconvenient, and sometimes you might forget to come back. So we emphasize you can safely do them together.”

The CDC said that extensive research on the simultaneous administration of the most widely used live and inactivated vaccines has demonstrated rates for adverse reactions similar to those observed when the vaccines are administered separately.

The CDC does note that “it is not known” if the reaction to COVID-19 vaccines is increased when given along with so-called “adjuvanted vaccines” that produce stronger reactions.

Adjuvanted vaccines like the shingles shot have added ingredients that produce stronger immune responses. Fluad, a flu vaccine for adults age 65 or older, contains an adjuvant made from a naturally occurring oil found in many plant and animal cells and has been used in the U.S. since 2016. The CDC says it “has an excellent safety record.”

Should older people get the shots separately? Dr. John Swartzberg, clinical professor emeritus of infectious diseases and vaccinology at UC Berkeley’s School of Public Health, said he’s getting his flu shot separate from his COVID-19 booster to minimize any reaction, but he said there’s no danger getting them together.

“It’s safe,” said Swartzberg, who’s had “modest” reaction to the COVID-19 vaccine but not to flu shots. “We don’t know if there’s more of a reaction, but there’s no danger in doing it in terms of a terrible reaction.”

The CDC says anyone with concerns about getting both vaccines at the same time should speak with a health care provider. Dr, Kavita Trivedi, Alameda County communicable disease controller, agreed and said “we have no reason believe the side effects will be increased with taking both at same time.”

How bad flu season might be this year is anybody’s guess. But health experts caution there are plenty of reasons to think it won’t be as mild as last year.

Swartzberg said last flu season was the lightest he’d seen in his 50-year career. No one’s sure why, he said, though it’s assumed the measures aimed at controlling COVID-19 — physical distancing, face masks, avoiding crowds, closing offices and limiting indoor activities — also kept influenza in check.

The CDC also notes that flu vaccination hit a record last season, which saw the lowest recorded hospitalizations from the disease since data tracking began in 2005.

Though flu vaccines aren’t always as effective as those for COVID-19 at preventing illness, averaging around 50-60%, they still reduce severity of illness, Roy said.

This season, people are expected to be mixing more on the job and in social gatherings with pandemic controls easing. On top of that, after a year with virtually no flu, more people may be vulnerable to it this season.

Swartzberg and other health experts noted many vaccines are routinely given in combination, both for adults travelling overseas and children entering school, including the diphtheria, tetanus and pertussis shot (DTaP) and the one for measles, mumps and rubella.

And it is possible to get both the COVID-19 virus and influenza at the same time, health experts say, and while there haven’t been a lot of those cases to draw conclusions from, Smith said “obviously it would be the best idea to prevent it.”

Kaiser and county health officials say they are well stocked with both COVID-19 and influenza shots and ready to give both together in most sites. COVID-19 vaccines are free and flu shots are covered by most health plans and typically available free to those who aren’t insured.

“We are anticipating a robust influenza season this year,” Trivedi said. “So we want to make sure as many people get vaccinated before the respiratory season hits us very hard, and make sure they continue to be protected from COVID-19. Both vaccines remain incredibly important.”