Читать книгу Vaccines For Dummies - Sharon Perkins - Страница 29

There’s one virus that everyone notices when it spreads. Norovirus spreads quickly in schools, hospitals, and cruise ships. It spreads mostly by fecal-oral transmission, meaning it spreads when tiny particles from one person’s stool (or vomit) get into someone else’s mouth. This can happen by direct contact with another person, when food or water is contaminated, or by touching surfaces that someone who is ill has touched. Norovirus can also be aerosolized, spreading in the air to people nearby. This can happen when we flush a toilet or vomit, sending tiny particles into the air that others swallow when they breathe.

It doesn’t take much to infect us with norovirus. Our stool can contain billions and billions of virions, but it may take somewhere between ten to 100 of these to infect us. There can be asymptomatic spread.

Infection usually happens fast. We usually get sick 12–48 hours after exposure. Symptoms mostly include vomiting and diarrhea. This can lead to dehydration, along with muscle aches, headaches, and weakness. Usually there isn’t much of a fever — if anything there’s a low-grade fever. Most people get totally better in two to three days, but norovirus can be serious for folks with other illnesses or who are elderly and can’t tolerate the dehydration. A little under 1,000 people are thought to die from norovirus a year in the United States, mostly among the elderly, and over 100,000 need to be hospitalized.

There isn’t a vaccine or a specific treatment for norovirus. Rehydration — often with Pedialyte or an oral rehydration serum and sometimes with IV fluids — is what gets us through the dehydration.

Some people are immune to some types of norovirus thanks to a gene (FUT2) that they are born with. But this works against only some genotypes of norovirus. There are ten main groups and at least 48 different genotypes.

Others develop immunity to specific types after getting sick, but not to all the genotypes, and it’s not clear how long this immunity lasts.