Sweden's Public Health Authority announces the start of the season each year, based both on the number of searches on its online service 1177 Vårdguiden and on statistics from its laboratories across the country. Now that the season has started, it will provide weekly updates on the spread of the illness.
“The only comfort for those who get sick is that it passes relatively quickly,” said epidemiologist Elsie Ydring.
It's too early to predict how much the illness, called vinterkräksjuka, is likely to spread, although recent years have seen relatively mild outbreaks. The number of infections is expected to increase over the coming weeks, so it's prudent to take extra care of hand hygiene especially over the busy Christmas season.
There is no vaccine or medicine for the bug, and disinfectant hand gel doesn't work against it.
“You should wash your hands carefully with soap and water to protect yourself against the infection,” said Ydring. Hand gel can be used after hand-washing to protect against other bacteria and viruses, however.
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“It is often a sudden sickness, you feel good in the morning but bad by lunchtime. Most often, it passes within 24 hours,” said Ydring.
If the symptoms persist or the affected person is a small child, it might be worth contacting a doctor.
“A tip is to first call 1177 and ask for advice on whether you should go to the doctor or not. In this way, you reduce the risk that you end up infecting others in a waiting room at the GP surgery or an emergency unit,” the epidemiologist recommended.
It comes just a few days after the season for the winter flu, a different illness, was announced by the Public Health Authority.
Most cases of vinterkräksjuka usually occur between November and April, reaching a peak in February (sometimes called vabruari in Sweden, because of the high numbers of parents who take time off to look after sick children, called vabba in Sweden).