The move indoors during colder months may not drive up Covid-19 numbers on its own, an expert has said.
Instead, a behavioural change with people from different households mixing and possibly not wearing masks could be a potential way for the virus to spread.
Professor Ben Neuman, chairman of biological sciences at Texas A and M University-Texarkana, and visiting associate professor at the University of Reading, said the winter could potentially have some benefits.
He said: “The move indoors for the winter may not be likely to drive up Covid-19 numbers on its own.
“A cold winter can bring on its own mini-quarantine, as we stay home to avoid bad weather, and comes with a bit of natural PPE in the form of scarves and gloves.
“Instead, look for changes in behaviour that lead to mixing of people from different households, especially where masks would not be worn, as a potential source of Covid-19 – school reopenings, dinner parties, restaurants.”
He added that some analysis leans too heavily on the influenza virus – which peaks in winter - but that most viruses are not as strictly seasonal as the flu.
Some normally peak in spring, including most coronaviruses, and others peak in summer or autumn, like poliovirus.
He added that after the coming flu season there will be a lot more data and that any conclusions at this stage would be speculative.
However, Prof Neuman highlighted that the similarity of symptoms between Covid-19 and flu could result in an increase of negative coronavirus tests, giving the wrong impression that the virus was decreasing.
He said: “A possible side-effect of flu and Covid-19 season is that since both diseases start off with similar symptoms, more people will be ill enough to seek Covid-19 testing.
“Paradoxically, an influx of people with the flu seeking Covid-19 tests could potentially drive down the percentage of positive tests, which would then misleadingly suggest that Covid-19 was decreasing.
“That is one reason why per cent positive rates should not be taken in isolation to monitor the pandemic.”
Dr Julian Tang, honorary associate professor in respiratory sciences at the University of Leicester, said ventilation would play an important role in the spread of the disease and people needed to continue wearing masks.
He said: “Anything you do to mitigate Covid-19 as an individual PPE intervention may well be the only thing you can do, because increasing ventilation – opening windows – will work in some situations.
“But a lot of indoor areas, indoor buildings, cannot ramp up ventilation very well with existing systems, and some of the windows are not openable.”
He said that he is part of a network of experts that indicate it may be necessary to open windows, with the heating on.
Speaking about classrooms, Dr Tang said: “What they suggest is that you have to turn on the heating with the windows open, which is a terrible waste of energy.
“But what that does is it creates convective flows that may actually enhance the ventilation in those classrooms.
“But again, if you’re wearing masks, to some extent this will be helpful, but you have to remove the airborne virus that may be expelled over the hours to actually make those masks work.”