The problem with flu is that it is highly variable, having a chromosome in 8 pieces that can rearrange in a cell that is infected by 2 strains. A cold is a very superficial in its contact with the immune system, so does not elicit a strong immune response. We should not assume it will be a measles type immunity, but the probability is that immunity will be longer lasting that colds and the virus less variable than flu.
Cold/flu strains fall out of circulation with some regularity!
The deadly viruses that vanished without trace
For years, it was thought that the influenza A strains we live with are constantly evolving to be better able to infect us. But the latest scientific research shows that this is not the case.
It turns out that anyone who died before 1893 will never have been infected with any of the influenza A strains that exist today. That’s because every flu virus that existed in humans until about 120 years ago has gone extinct. The strain that caused the 1918 pandemic has also disappeared, as has the one that led to the 1957 avian flu outbreak, which killed up to 116,000 people in the US, and the type of flu that was circulating in 2009, before swine flu emerged.
Secondly, certain virus strains, like the types of Covid-19 – of which there are already at least six – might amass enough mutations that are harmful to themselves so that they disappear altogether. In India, there’s already evidence that this could be happening naturally. The virus is mutating at a staggering pace, and it’s been suggested that it might be heading for an evolutionary cliff all on its own.