Covid infections are putting people at higher risk of diabetes, strokes, heart disease and other long-term illnesses – but experts warn it may be decades before the full impact is known.

Meanwhile, could Covid-19 also be blamed for the increased frequency and severity of colds and flu? Has it damaged our ability to fight off infections?

Northland emergency doctor Gary Payinda said some viruses, which used to cause barely a sniffle in healthy adults, were now putting people in hospital.

“We’re now seeing your typical regular healthy middle-aged person presenting to ED with bad cases of RSV. And that’s pretty novel for us,” Payinda said.

He suspected Covid may have damaged people’s immunity in subtle ways that fell below the threshold to qualify as long Covid.

Several international studies – involving millions of people, mainly from before vaccines became widely available – found a Covid infection doubled the risk of developing heart disease and increased the chance of stroke 1.6 fold.

It was also associated with higher rates of both type 1 and type 2 diabetes.

“There are a lot of long-term sequelae to Covid that we don’t really know yet and we may not know for years,” Payinda said.

“Post polio syndromes were not identified for literally decades after polio infections. The same with the 1918 flu epidemic – people born during the 1918 Spanish flu epidemic had a two- to three-fold increased risk of later developing Parkinson’s Disease.”