When is a person with COVID-19 infectious, and can they transmit the virus to others before symptoms appear? If you have COVID-19, you are currently considered infectious generally from 48 hours before your symptoms develop (or before your positive test if you don't have any symptoms).
You can also spread COVID-19 in the 48 hours before your symptoms start. If you never have symptoms, consider yourself most infectious in the 5 days after you test positive.
The time from exposure to symptom onset (known as the incubation period) is thought to be two to 14 days. Symptoms typically appeared within five days for early variants, and within four days for the Delta variant. The incubation period appears to be even shorter – about three days – for the Omicron variant.
People with COVID-19 can spread the virus to other people starting two days before they develop symptoms (or 2 days before the date of their positive test if they do not have symptoms) through 10 days after they develop symptoms (or 10 days after the date of their positive test if they do not have symptoms).
You can have COVID-19 and spread it to others even if you do not have symptoms. Your COVID-19 test can be negative even if you are infected. Most people do not test positive for the virus until days after exposure. You may also be exposed to the virus afteryou are tested and then get infected.
Most often, common cold symptoms start 1 to 3 days after someone is exposed to a cold virus. Symptoms vary. They can include: Runny or stuffy nose.
The Delta variant's was 4.41 days. And Omicron's has been 3.42 days. Taken all together, the average incubation period of COVID between December 1, 2019, and February 10, 2022, was 6.57 days. Even though the incubation period is shorter, COVID-19 still has a longer incubation period than other respiratory infections.
When do omicron subvariant symptoms start? The time it takes for an infected person to develop symptoms after an exposure is shorter for the omicron variant than for previous variants — from a full week down to as little as three days or less, according to the Centers for Disease Control and Prevention.
You can spread the common cold from a few days before your symptoms appear until all of the symptoms are gone. Most people will be contagious for up to 2 weeks. Symptoms are usually worse during the first 2 to 3 days, and this is when you're most likely to spread the virus.
Some people can test positive for COVID-19 for weeks or even months on PCR tests, but there is good news: people are not likely to be contagious for that long from a single infection, even if they test positive, and therefore are unlikely to transmit the virus to others.
Cold symptoms usually begin 2 or 3 days after exposure to a source of infection. Most colds clear up within 1 week, but some last a bit longer.
Symptom onset
The first symptoms of COVID-19 can be more gradual. While COVID-19 symptoms can develop as early as two days after you're infected, the Centers for Disease Control and Prevention (CDC) says five days after infection is typical.
BMJ: “Covid-19: Runny nose, headache, and fatigue are commonest symptoms of omicron, early data show.”
In infected individuals, the peak viral load occurred on day 5, with the virus first detected in the throat and then rising to significantly higher levels in the nose.
The median incubation period of COVID-19 is 5–6 days, ranging from 1 to 14 days. The infectious period remains uncertain; however, it is estimated to be from 48 hours before symptoms develop until two weeks after symptom onset.
How long is the common cold contagious? The cold can be spread for up to two weeks, including before symptoms even appear. In fact, you will have the ability to spread the cold virus to others for a few days before your symptoms begin.
Symptoms of a cold tend to be mild. You may have a runny nose, cough, congestion, and sore throat. But you won't usually have the aches and fever that are common with COVID-19 and flu. Often, you'll feel better in a couple of days.
If you are significantly immunosuppressed, you are more likely to be infectious for longer than 7 days and may still be able to spread the virus. Follow these measures until day 14 following your positive test result to further reduce any remaining risk of spreading the virus.
It can make you feel dull and tired, take away your energy, and eat away at your ability to get things done. Depending on the seriousness of your COVID-19 infection, it may last 2 to 3 weeks. But for some people with a severe infection, the brain fog-like fatigue and pain can linger for weeks or months.
The research shows that covid-19 headaches are most similar to either tension headaches or migraines. The symptoms of tension-like headaches include: Moderate or severe pain. Pain on both sides of the head.
A dry cough is one of the most common coronavirus symptoms, but some people may have a cough with phlegm (thick mucus). It can be difficult to control your cough but there are a few ways to help.
People with moderate or severe COVID-19 should isolate through at least day 10. Those with severe COVID-19 may remain infectious beyond 10 days and may need to extend isolation for up to 20 days.