As the southern hemisphere enters its winter season, it seems like flu season is running a little behind.

Lockdowns and distancing measures are designed to prevent the spread of the novel coronavirus that causes COVID-19, but they might be affecting other diseases too, early data suggests.

In a report on respiratory illnesses looking at this year up to May 17, South Africa’s National Institute for Communicable Diseases noted that the 2020 influenza season has not yet started in that country and reported cases so far have been “much reduced.”

Similarly, the RSV (respiratory syncytial virus) season, another respiratory illness, has been “substantially delayed,” according to the report, “possibly in part due to the national lockdown.”

The institute notes, however, that since lockdowns started, fewer patients have enrolled in their virus surveillance programs, which may have affected numbers as well.

Story continues below advertisement

“What we do know is that bacteria and viruses do not travel independently,” said Tom Koch, an adjunct professor at the University of British Columbia who specializes in disease mapping. “They arrive and are transferred by human travellers.