I’ve had the flu a few times in my life and while it was pretty miserable I got better in a week or so. Are these “pandemic” flus the same thing but they are killing people with weak immune systems or are they a whole different animal than everyday flu?
Same “species”, different strain. They occur when the “really really deadly” gene set happens to combine with the “really really easily spread” gene set.
Pandemic is when a flu bug comes into being that has all the contagiousness of the usual human flus but that also has outside bits (antigens) that humans have no protection for. The ways in which flu bugs mix up their genes makes this something that is bound to happen eventually … again. Genrally they happen when a human gets a usual contagious human flu and an animal flu at the same time and the bugs mix up their chromosomes creating one with the previously unknown to people (and thus more deadly) animal flu bits along with the catchy to human human flu bits.
The 1918 flu was worse for people with nice healthy immune system.
I think the issue is when a flu virus jumps to a new species, the new species system is not ‘primed’ by exposure over the years to many similar viruses.
Once you have contracted a virus, you are immune to it. If you are exposed to a very similar virus, your existing antibodies can keep it in check until your immune system creates the anti-bodies to the new virus.
If you body has never seen anything like the new virus before, the virus has it’s way with your body, unchecked until the antibodies are produced; sometimes the immune response is so extreme, it essentially kills you. Drowning your own white cells, sort of.
I eagerly await the corrections from any professionals out there.