So what happens when flu meets Covid-19 in Ireland this autumn and winter?
The chilling prospect of a double whammy of killer infections has the potential to impact our death rates.
The spread of infection could increase as more of us huddle indoors during colder months - with the health service predicting this will be a winter like no other.
However, we know now that when it comes to the Covid-19 pandemic - while there are no predictions, just possibilities - we have to prepare for the worst.
Every year, a flu vaccine is prepared which is aimed at targeting the strains that are expected to circulate.
This was completed in spring and the hope is that the jab will be an accurate match for the kinds of flu which will dominate this winter.
The nightmare scenario would be if the seasonal jab is not effective because of variance in strains.
GP surgeries are facing a flood of calls this winter from people suffering with symptoms that could be linked to Covid-19, flu or a heavy cold.
More people will get the flu jab for free this season but thousands will not.
The extension includes younger children, making it the first time these youngsters are recommended to get the jab.
Asked yesterday why it will not give the flu jab free to everyone, the Department of Health said the approach taken by the HSE and the Government to extend the vaccination programme for winter is to ensure that those who are most vulnerable to the winter flu will have access to vaccination without charge.
This includes those in at- risk groups and healthcare workers.
The extension of the vaccination to all children aged from two to 12 years will provide additional protection, the spokeswoman said.
She said this is in line with the advice of the National Immunisation Advisory Committee and represents a significant step forward in providing vaccination without charges.
Around two million doses of the flu vaccine are on their way here. They include 1.4 million doses for the usual target groups and an additional 600,000 for the campaign to vaccinate children.
Evidence from around the world indicates that if there is an uptake of 40pc to 50pc in the children's age group it will have a significant impact on flu in the overall population.
The HSE doctors say the flu vaccine works well for some individuals but it works best at a population herd level.
They say that international experience shows it is even better if we focus on children.