Anonymous asked in HealthDiseases & ConditionsInfectious Diseases · 9 years ago

why do people get reinfected with the cold wirus after year after year?

why dont they have immunity after one infection

4 Answers

  • 9 years ago
    Favorite Answer

    There are an infinite amount of branches of the cold virus. When you get a cold, and it gets better after a little while, you are then actually immune to that particular branch, because your body has conquered it. But then you can easily get a new cold from a new virus.

  • Anonymous
    9 years ago

    There are two reasons for this.

    The first reason is that there isn't just one virus that causes the common cold. There are about a hundred of different so-called Rhinoviruses all of which can cause the common cold, and there about 200 other viruses with the same symptoms. The immune system is very specific in remembering pathogens, so if you get the common cold from rhinovirus 1 and the next month from rhinovirus 2, your immunity from 1 won't protect you.

    The other problem is that some viruses evolves at a incredible fast pace. You might be immune for a version of the virus now, but within a year or so it might have changed so much that your immune system doesn't recognize it anymore and will need to redevelop immunity.

    Source(s): 2nd year student Bachelor biomedical sciences
  • 9 years ago

    Because, just like every other organism, viruses evolve. So when you got a flu shot last year, it was for the strain that year. The virus has since then evolved to the point where if you were to come into contact with it this year, it would be different enough where your body wouldn't recognize it.

  • 9 years ago

    The reason is that there is not just one virus that causes the "common cold". There are hundreds of viruses that cause the symptoms we diagnose as the common cold.

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