China is battling a surge in cases following its decision last month to lift years of lockdowns, quarantines and mass testing that had hammered its economy and sparked rare nationwide protests.

The virus is most likely to spread through inhalation at close range rather than through contact with surfaces or at long range, they say.

But the team tasked with examining potential meteorological and air quality influences on the spread of Covid-19 says weather and climate conditions alone should for now not be the trigger for loosening restrictions.

The studies by Swiss scientists show that the chances of being infected this way is 'less than five in 10,000'.

But there is no doubt that children are generally asymptomatic or have less serious forms of the disease compared to adults.

The study concludes that even on a full plane, the level of transmission over 12 hours of flight is negligible.