Annual flu rates have dived in the southern hemisphere with infections in some areas down to a fraction of their usual numbers for the season, with medical officials saying that restrictions to limit coronavirus infection rates were having a similar impact on flu transmission.
In Australia, from January to June there were 21,000 people diagnosed with flu compared to 132,000 during the same period in 2019. There have been 36 deaths, compared to 430 the year before.
South Africa has also seen a decline, with recent reports showing there have been 85 cases of flu this season, compared to 22,000 last year in the same period, Channel 12 reported Monday.
In Argentina there has been a 64% drop in reported flu cases from 4,210,000 to 151,000 this year, the report said, while in Chile there have been just 1,100 cases of flu this season where as last year there were 210,000.
The first two weeks of July, usually the height of the annual flu outbreak in Chile, there were no cases, the report said.
Australian Medical Association NSW vice-president Andrew Zuschmann told ABC Australia last week that the figures for the country show that measures taken against the coronavirus spread were also holding back the flu.
“What it’s telling us is that many of the measures that are working to contain the spread of COVID-19 within the community are also very effective at reducing transmission of influenza,” he said.
Another factor that appears to have played a role is the drastic reduction in international air travel. Each year there are new strains of influenza but with flights reduced and travel restricted, the flu has not been carried across borders, preventing its spread, Channel 12 reported.
The impact on annual flu infections of measures taken by countries to curb the coronavirus pandemic have also been noted in the northern hemisphere.
In May Nature magazine reported that lockdowns and social distancing appeared to have shortened the annual flu season in the north by six weeks.
“Public-health measures such as movement restrictions, social distancing and increased personal hygiene likely had an effect on decreasing influenza and other respiratory virus transmission,” the World Health Organization said in a statement at the time to Nature.
In April, the Lancet medical journal published a report on a shortened flu season in Hong Kong, brought about by a response to the coronavirus that was spreading across the world.
The report found “non-pharmaceutical interventions (including border restrictions, quarantine and isolation, distancing, and changes in population behavior) were associated with reduced transmission of COVID-19 in Hong Kong, and are also likely to have substantially reduced influenza transmission in early February, 2020.”
The report authors, who conducted a telephone survey to assess behavior during the coronavirus outbreak, found that by mid-March some 99% of residents were wearing face masks when they went outside their homes.
In Melbourne, Australia, where there has a been a major virus outbreak, face masks became compulsory last week. In Hong Kong, face coverings in public places will be mandatory from Wednesday.
The trends could lessen concerns raised by Israeli health officials who have said the medical system could become overwhelmed during winter as flu patients are added to those suffering from the coronavirus.
Health Ministry figures released Monday showed that four major Israel hospitals were at or close to their maximum capacity.