A clutter of unhelpful pandemic rules is wearing people down. One-way systems in stores, outdoor mask mandates, ceaselessly cleaning groceries and packages — should these things be our top priorities for limiting the spread of Covid-19?

Harvard’s Joseph Allen is an associate professor of exposure assessment science and one of the world’s experts on why some indoor spaces are worse than others for spreading viruses. Like other experts, he agrees that poorly ventilated indoor sites are the prime spreading ground for Sars-CoV-2. So the longer people spend in any indoor space with other people, the greater the risk they pose to themselves and others.

I asked him: Wouldn't it be better if we did away with the one-way system so that people could dispatch with their grocery shopping quickly, without having to endure long waits behind price-comparers or other slowpokes? The answer is yes. Eliminating those annoying arrows would probably make shopping safer as well as less stressful.

Businesses are, of course, free to impose their own rules, but it is unlikely many would knowingly make shopping less safe. The fault lies with the public health community for being too shy in talking about which rules don’t help, leaving us with a tangle of rules and recommendations — and pandemic fatigue.

State rules have an even bigger effect on our lives and are often thrown at people with no transparency. My state of Rhode Island has recently become one of the worst five states for per-capita infections, despite getting praise from Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, at the end of the summer for our strict rules and good compliance. With cases already climbing in late November, the governor Gina Raimondo held a news conference where she scolded citizens for not following the rules.

Soon afterward, a talk radio host voiced what I was thinking. Who are these people filling up the hospitals? Where do they live? What kind of work do they do? Do we have any idea how they got the virus? And which rules, exactly, were they breaking?

As risk communication consultant Peter Sandman has said early in the pandemic, a public health policy that people don't follow is a failed policy. That means even a really solid, science-based set of rules can fail if it's not communicated with a clear rationale.

In Massachusetts, the governor Charlie Baker has focused his latest round of rules on outdoor mask-wearing — something that many experts have said is unlikely to help since the virus is extremely unlikely to be transmitted over distances outside. The British Scientific Advisory Group for Emergencies has deemed outdoor mask-wearing of negligible benefit.

Baker’s ruling prompted Harvard epidemiologist Julia Marcus to suggest in Boston.com that he is playing pandemic theatre. “Arbitrary public health rules are a way to break the public’s trust, which is essential to keeping people engaged in public health efforts,” she told a reporter for the site. “I think a mandate like this — that people know is arbitrary — is going to do more to reduce trust than it will to reduce infections.”

Harvard’s William Hanage, who studies infectious-disease dynamics, told me that people don’t need more rules. They need more information about how the virus is transmitted so they can take steps to avoid it. “When you phrase things in terms of rules, it leads people to try to come up with ways to get around those rules,” he says.

Rules can become a form of misinformation. The rules in many states seem to suggest that walking outside is dangerous and eating in a restaurant is safe, but Hanage says the truth is the other way around.

Baker has justified his outdoor mask mandate by saying it sends a message. The message I heard was that the rules are not chosen for our health and welfare but to make our political leaders look like they are doing something.

Rules should only be decreed along with evidence for their benefit, argued statistician and risk communication expert David Spiegelhalter in a piece for The Guardian: “Too often, the message is shaped by communication professionals working to ensure the greatest number of people 'get the message' rather than thinking about how to present the evidence so the greatest number of people can understand it, trust it, and then decide for themselves.”

I hear from diverse readers who want to do the right thing, but need to know where to focus their efforts. A farmer in Florida recently wrote to me about the pandemic fatigue that is affecting him and his neighbours: “What happens here is that we get worn out, beaten down and overloaded such that no matter how well-intentioned we are we are prone to latch on to something wrong.”

He added: "So I think people here get it that it’s serious … they like their neighbours and don't want them dead.“

But they are wondering how much effort to put into disinfecting groceries and kitchen counters — something that some media outlets recommended in the spring, as well as wearing gloves at the gas station, disinfecting credit cards and letting packages sit outside for a few days before opening them.

Harvard disease expert Hanage says that the science to date points to the primary risk coming from what he calls the three Cs — close contact, closed spaces and crowds. He says in Japan, where they have had few Covid-19 deaths, people are advised to avoid these — not just to wear masks in these situations, but to limit them or avoid them altogether.

One place where the informational clutter can get sorted out is the Centres for Disease Control and Prevention. In an encouraging trend, the agency is starting to make recommendations by explaining why they are likely to improve public health. The agency cited good reasons people should avoid travelling for the holidays, including many combinations of those three Cs.

They have just issued new guidelines recommending masks when people are indoors outside their homes or cannot stay more than six feet away from other people. And they have just shortened the quarantine period for people exposed to the virus from 14 days to ten, or seven if you get a test at the end. Again, the rationale was explained — some cases can incubate for two full weeks, but most people develop symptoms sooner. A shorter quarantine period can still cut down on transmission and will get better compliance.

It would be wonderful if the CDC could also start telling us which rules and recommendations are unlikely to work, so we can all concentrate on the ones that will. There is some denial out there, but there is also enormous curiosity and willingness to help. It’s a resource we cannot afford to keep squandering.

• Faye Flam is a Bloomberg Opinion columnist. She has written for The Economist, The New York Times, The Washington Post, Psychology Today, Science and other publications. She has a degree in geophysics from the California Institute of Technology