1. Health
You can opt-out at any time. Please refer to our privacy policy for contact information.

People with H1N1 (Swine Flu) Contagious for Longer than Thought

By Julie Stachowiak, PhD
Multiple Sclerosis Guide; Guest blogger

There seems to be more bad news about Swine Flu, or H1N1, which may explain why it is spreading so quickly. In two new studies, researchers found that some people infected with H1N1 kept shedding virus much longer than the 7 days that people with seasonal flu shed virus - even up to 12 days in one study. What are the details and what exactly does this mean in real terms?

  • “Viral shedding” refers to the release (“excretion” in medical terms) of live virus from an infected host.
  • This lengthy period of viral shedding may mean that the CDC recommendations to stay isolated from people until you are symptom-free for 24 hours are not long enough, as people may still be contagious after this time. In fact, it now looks like people may be contagious for 3 or more days after their fever breaks.
  • It also looks like people may still be shedding virus after they are treated with Tamiflu, however, people who did not receive Tamiflu were contagious longer.

It is hard to know exactly what these studies mean in terms of really contributing to new infections, because: a) the scientist only knew there was some virus, not how much (so don’t know if it was enough to infect someone), and b) the test used was polymerase chain reaction, which detects the DNA (in this case of the H1N1 influenza virus), which it can often detect even if the virus is dead - at which point it would be harmless.

What does this mean to you? Well, it means that you don't want to necessarily rush over to your friend's house with the whole family just because she hasn't had a fever for a day - you may want to wait a little on that one. It also means that if you are the one who had H1N1, if at all possible, take a couple of extra days to stay home and take care of yourself. Your body is still healing at this point and needs the rest and you would do people a huge favor by not bringing them into contact with potentially infectious virus.

September 16, 2009 at 8:52 am
(1) Good clinical practice says:

good personal hygiene is a key factor…

June 3, 2012 at 3:44 pm
(2) Carolyn says:

I have friend who is having severe long term effects
quite possibly from the h1n1 vaccine.
Taking over her lungs rapidly. Immune system
Is not functioning. Blood levels off the charts.
Primary Dr thought phenumona at first.
Pulmonary specialist is stymied. Has done CT
Scan and tested for cancer, copd, emphasyma
Aids. Gave her a script for oxygen and will do
a biopsy in a few weeks. She became extremely
ill after she had the h1n1 vaccine last yr.
Viruse in both lungs now. Could she be contagious
and have swine flu? Is it possible?

Leave a Comment

Line and paragraph breaks are automatic. Some HTML allowed: <a href="" title="">, <b>, <i>, <strike>
  1. About.com
  2. Health
  3. Infectious Diseases

©2014 About.com. All rights reserved.

We comply with the HONcode standard
for trustworthy health
information: verify here.