The emergence of the Omron variant, to try and ensure safe holiday parties and family gatherings, is making COVID-19 scramble for lateral flow tests. The UK is dealing with a lack of supplies for these cheap, fast tests – known in the US as rapid tests – after health officials last week said they were as effective at taking on Omicron as Delta, in the past. Most contagious strain.
In the US, New York is handing out free rapid test kits, while Vermont has issued a mandate that helps people cover testing costs through their insurers that could soon become a federal requirement.
When should you get tested after possible exposure to COVID-19?
According to Irene Peterson, professor of epidemiology at University College London, the best time to test is two or three days after coming into contact with someone with the virus. This is because it changes when people start being contagious. If you are sitting next to someone who had the virus on Friday, you should get tested on Monday.
I’m going to the Christmas party. When should I get tested?
Just before leaving his house, Peterson said. Don’t rely on a two-day-old negative test saying, “You might have been contagious in the middle.”
Can I count on a negative lateral flow result?
Don’t rely on a test taken a few days after exposure, Peterson said. You should continue to be tested for about a week after being exposed to the virus.
So you tested positive. now what?
It is best to rely on the rapid test first.
“If you get a positive lateral flow test, it’s very likely that you have COVID,” Peterson said. The chance of getting a positive lateral flow result is 99.97% when you don’t have the virus.
The official line in the UK is after a positive rapid test, you must undergo a PCR test and self-isolate until you can confirm your result. If the rapid test comes back PCR positive within two days, you should start isolating for 10 days. If you take a PCR after that, whatever the result, you will still need to isolate for a full 10 days.
Peterson advises people to stay home straight after a positive rapid test, especially if they start showing symptoms. “If you have a fever or runny nose, and a positive lateral flow test, it’s contagious,” she said.
What is the difference between Rapid Test and PCR?
A lateral flow test checks whether you have protein from the virus in your body. You are likely to have high levels of these proteins when you are most contagious – so this may be less accurate after infection or at the end of your illness. It is also known as rapid test because it can be taken at home and you get the result in less than 15 minutes.
A PCR test, which identifies the genetic material from the virus, must be examined and interpreted by a laboratory. It can take up to two days to get your results, and they’re also more expensive than lateral flows. PCRs are more sensitive at picking up viruses, because the genetic material you may have in your samples is amplified in the laboratory. That is, it can catch the disease before the rapid test. According to the Robert Koch Institute, a PCR can detect the virus up to two days after infection and up to 16 days after infection.
With PCR you can test positive even if you are no longer infectious, because you may still have some genetic material from the virus, Peterson said.
How do you get your hands on a lateral flow test?
In England, you can take a rapid test from a pharmacy, order a kit from a list of providers available on the government website, or you can visit a test site. Schools, colleges and nurseries and some employers and universities also offer rapid tests free of charge.
This story has been published without modification in text from a wire agency feed.
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