Staying home during the Covid-19 pandemic was an invaluable public health measure that helped to greatly reduce transmission of the virus and save many lives (at least more than the incredible amount of people we lost).

But life in lockdown certainly isn’t typical for most of us. It has raised questions about what a year of relative isolation, masking and just general germ-avoidance may have done to our immune systems. Have they been wrecked? Are we basically just babies reborn? Do we need to behave differently now?

Of course, many people have been working and learning in-person for months now, while others are just starting to re-emerge. So here is what we know about what happened to people’s immune systems during the pandemic, as well as what to expect as even more people dive back into their old routines. 

Most adults’ immune systems will NOT have been weakened by isolation

Perhaps you’ve heard about the hygiene hypothesis, which is the idea that exposure to certain viruses, bacteria or parasites in childhood helps the immune system develop. Based on that theory, some people are worried that people’s immune systems will be walloped when they go back out into the world, because they haven’t been exposed to many germs over the past year-plus. But experts aren’t concerned.

“There is no cause for concern that social distancing has weakened our immune systems,” Sindhura Bandi, an allergy and immunology specialist and associate professor of medicine and paediatrics with Rush University Medical Center, told HuffPost. “By adulthood, we have come into contact with many types of viruses and bacteria. Our immune system has created memory to these pathogens, so that when we come into contact with them we can make antibodies to fight off the disease.”

In other words, your body has already spent a lifetime developing antibodies to common illnesses through direct exposure or through vaccination, Bandi explained. One year of staying home and masking (which again, helped fight a deadly pandemic) is not going to drastically change that. 

That said, you might come down with a cold when you head back into the office ― because you’re going to be around more germs again, and because, yes, your immune system is a bit out of practice.

“Our immune systems have not been exposed to common everyday pathogens,” explained Monaa Zafar, a doctor of internal medicine with Westmed Medical Group. She also noted that people’s immunity may have been hampered by other lifestyle changes over the past year — like the fact that many people have been drinking more, sleeping less, coping with chronic stress and not getting outdoors and getting sufficient vitamin D.

Experts also have questions about what the 2021-2022 flu season could be like after being virtually nonexistent this past year. There’s some speculation it could be particularly bad as experts struggle to predict which strains to target with next year’s vaccine, though no one really knows.

But concerns about a potentially tough flu season don’t have anything to do with people’s immune systems and being sheltered in 2020.

People who had Covid-19 might have long-term immune system changes that we don’t totally understand yet 

While most adults’ immune systems haven’t been changed by the pandemic, some people who were infected with Covid-19 and recovered could, indeed, experience some long-term alterations to their immune system function.

“Some patients experienced a significant inflammatory response as the immune system worked to fight the disease,” Bandi said. “Recovery from the illness has led to long-term effects ― commonly referred to as ‘long Covid’ ― which may be tied to the immune system.”

Experts are still unravelling what causes some people to come down with long-haul Covid ― or post-acute sequelae of SARS-CoV-2 infection (PASC) as it is now officially known ― as well as what causes it. One working theory is that lingering symptoms may stem from a persistent inflammatory or autoimmune response.

What all of that means in terms of people’s immune system function as they head back out into the world is still a question — and a pressing one. Estimates suggest up to 1 in 4 Covid-19 patients are long-haulers. 

Kids might get more colds

There is a chance that young kids who’ve missed out on a year of nursery or school could be prone to more colds and other infections when they begin spending more time together again.

“There are studies that demonstrate that toddlers who attend congregate child care settings, and presumably are exposed to more germs, are less likely to develop viral illnesses, allergies and autoimmune diseases in school,” Bandi said.

But context is really key here. Sure, young kids might have a harder time fighting off some common illnesses when they get back to their old routines, but it was essential to keep them isolated for much of the year because it lowered their risk of getting — and spreading — Covid-19.

Also, they still have ample opportunities to be exposed to germs down the road.

“As the general population becomes vaccinated and we are able to open up again, these young children will have plenty of opportunity for their immune systems to become exposed to and make antibodies to common childhood cold viruses,” Bandi said. 

Sleep, socialisation and staying home when sick will all be really important

Ultimately, there’s no clear scientific evidence that if you engage in certain habits or behaviours you can really directly “boost” your immune system, but taking care of your overall wellbeing certainly won’t hamper how it functions. Doing things like getting plenty of sleep and loading up on nutrients are always good ideas.

“Getting six to eight hours of sleep nightly, 150 minutes of exercise weekly, eating whole grains, lean protein, fruit and vegetables in a balanced diet all help strengthen our immune systems,” Zafar said. 

“I believe the most powerful immune-booster is regular physical activity,” echoed Tuvana Bain, a doctor of internal medicine with Westmed Medical Group. 

There’s been a lot of talk about how important social connection is for our mental health and well-being, but there may be an important immune-system element to reconnecting with friends and loved ones as the world slowly reopens as well. 

“As people are able to connect again with family, friends and colleagues, this can have an indirect effect on boosting the immune system,” Bandi said. Indeed, research has linked loneliness to all kinds of poor physical outcomes, from heart disease to decreased levels of certain antiviral compounds in the body.

Lastly, it’s going to be really important over this next stretch to avoid the tendency to go into the office or send your kid off to school when sick. Staying home and resting not only gives your own immune system a chance to fight back, it also helps keep other people safe. 

“In the past, we may try to stick it out for the workday or give our child some Tylenol before sending them off to school to suppress the fever,” Bandi said. “We have to remember there are vulnerable people around us.”

The good news is, most of us have become much more attune to how our own behaviours impact the health of others, and we’ve become pretty darn good at basic preventive measures.

“Nothing beats frequent hand-washing as the ultimate protection from infection,” Bain said. 

Experts are still learning about COVID-19. The information in this story is what was known or available as of publication, but guidance can change as scientists discover more about the virus. Please check the Centers for Disease Control and Prevention for the most updated recommendations.