How Long Can You Be Asymptomatic (And Why)?

Exact Answer: Depends On The Disease  

Several diseases can be in a patient’s body for months to years before symptoms start showing. It is important to understand the timeline of these illnesses because early detection and treatment could mean the difference between life or death.

The body is an amazing machine. It can go through a lot of wear and tear before it needs to be replaced, but sometimes the parts are so damaged that they need to be swapped out. When this happens, patients need to know what their options are. 

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How Long Can You Be Asymptomatic?

DiseaseIncubation Duration 
Bubonic Plague2 -8 days
Common Flu2 days

In the most severe type of plague, bubonic plague, an infected flea must bite a human to transmit the bacteria that causes bubonic plague. In this way, it is possible for nearly 100% of people living in a town or other community to be exposed without showing any symptoms. 

The incubation period (the time between exposure and onset) ranges from two days to eight days (median, three).

The common flu has an incubation period of about 2 days (48 hours). Hong Kong flu has an incubation period of 4 to 5 days; avian influenza’s incubation rate lasts approximately 2 to 5 days; AIDS can last as long as 10 years before any visible signs manifest themselves. 

HIV can go undetected by the body’s immune system for years, if not decades. COVID 19 virus can go undetected for up to 21 days. Many evidence suggests that one in 5 people face no symptoms when contacted by the disease.

The overall asymptomatic period depends on the virus and the people.

TB is not considered an asymptomatic infection, and influenza, however, can be dormant in one’s body for years. The longest documented person with chronic hepatitis C has been untreated for over 25 years without showing clinical signs of liver disease or infecting anyone else. 

Herd immunity is another factor that affects how one becomes symptomatic after infection with a particular microorganism. Some viruses select flare-ups when enough time passes since they were first infected to have new mucus membranes primed to respond.

Why Would Being Asymptomatic Take So Long?

It takes several weeks to months to be sure if a person has a particular disease. Symptoms usually, but not always, arrive within 1-2 days following infection, and they peak in the first few weeks of infection before gradually tapering off depending on the disease. 

This is part of how we diagnose illness with numbers – one has to take measurements and compare them against what is considered normal for that person over time or across population groups under different circumstances. 

One can’t expect to show up tomorrow with no symptoms and have it diagnosed after one retraction – cell repair is slower than attack, so it takes many days just for damage from an immune response to accumulate enough for doctors even to notice it. Perhaps the most telling symptom is that persistent mystery.

It can take so long because the virus remains in the body after one gets better. It’s important to understand how the HIV/AIDS virus works to keep themselves and their loved ones healthy. 

When one is infected with HIV, it enters into a stationary cell called a reservoir cell. These cells never die, complicate diagnosis and treatment immensely because they do not know or cannot see that they are infected. 

These cells don’t react to any of the chemical messengers that tell other stationary cells when there is an invader inside them busy multiplying for days. 


In the worldwide pandemic, self-isolation, masking, hand hygiene, and increased ventilation are beneficial, whether negative or positive. 

Another reason that scientists want to know how frequently individuals without symptoms transmit the virus is because these infections go unnoticed in most countries. The majority of testing is directed at those who are ill.

Even though there’s a reduced chance of transmission from asymptomatic individuals, they may still be a serious public health risk because they’re more likely to be out and about than isolated at home. 

Overall, one person can go asymptomatic for years before detection. Therefore, it is better to be careful.



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Hi! I'm Nidhi.

Here at the EHL, it's all about delicious, easy recipes for casual entertaining. So come and join me at the beach, relax and enjoy the food.

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