Can you be immune to something you haven't ever had before?

[Quixote1818]

Or do people with strong immune systems get the infection and their bodies react quickly and knock it out before symptoms occur?

I haven't ever understood why there is always a certain number of a population who seems to be immune to something new. For example the Native Americans had some who just never got smallpox. They seemed to be immune to it even though it was new to Native Americans.

[ECSkeptic]

1. Yes, you can.

...perhaps the virus enters the cell through a particular gate, and you have a gene that causes the gate to be in a different configuration that the virus can't enter. Perhaps you have a mutation in a particular enzyme that slows the reproduction of the invading bacteria, etc. etc.

One of the best examples is sickle cell disease, which actually makes sickle-cell carriers resistant to malaria.

[Quixote1818]

3. Thanks. Makes perfect sense especially when it comes to evolution

The more diverse a species biology is the better chance it has at surviving.

[Siwsan]

2. I've been exposed to people with flu, but never developed it, myself

I did get Shingles, but other than some discomfort, the rash and blisters stayed pretty minimal, it was over within about a month, with no residual scarring.

As a child, I had measles, mumps, chicken pox but never really felt "sick".

I just attribute it to having a strong immune system, that I take great care to maintain.

[CountAllVotes]

4. I have never had the flu

Since I quit smoking, I have not had a cold for over 12 years now.

I have a rare blood type and an rh factor and a compromised immune system due to a serious medical condition which is multiple sclerosis. I tend to be highly allergic to many medications and other things in life.

Persons with an rh factor tend to be more sickly than others but some with rh factors never seem to contract the flu. An rh factor means you have an extra layer of protein coating around the red blood cells and because of this, some think it offers some protection/immunity to the flu.

Both of my parents had the same blood type as I have and I do not remember either one of them ever having the flu.

Overall it seems to be very difficult to have immunity to a virus that has never been seen before however.

In any event, it is best stay away from crowds, etc.

Best of luck with your research re: this issue.

[DURHAM D]

5. I think it depends on your degree of Neanderthal DNA.

[Spider Jerusalem]

6. In certain instances yes

for instance I'm immune to norovirus because I'm an ABO "non-secretor" and don't produce the proteins the virus binds to.