Practicing good hand hygiene, maintaining a physical distance, and wearing masks can all break transmission chains and help control the spread of Covid-19.
So does testing. Specifically, Covid-19 testing.
Testing is the only way you can tell if you have Covid-19 or not. Knowing your status then allows you to better protect others and play your part in ending the pandemic.
If you test positive, you should take the important step to isolate and avoid transmitting the virus to others. Even if you don’t feel sick enough to seek medical care, knowing you are carrying the virus informs you to make better decisions about your health.
The majority of people who take Covid-19 tests are those that experience symptoms associated with the viral infection. But there’s a sizable group of people who do not develop symptoms when infected with the coronavirus that causes Covid-19. These people are described as being asymptomatic.
Are asymptomatic people infectious? Do they need to be tested and, if so, when should they get tested?
Let’s find out:
Can Asymptomatic People Transmit COVID-19?
Asymptomatic people can catch Covid-19, even though they may not be at any risk of illness. Once they contract the virus they can also transmit it to others.
That asymptomatic people do not get sick when they contract Covid-19 does not mean the virus strain they have is not potent enough to sicken other people. If you pass the virus to symptomatic people – particularly those who are not vaccinated – and those that are immunocompromised, they can get sick.
According to research studies cited by Medical News Today, as much as 40 percent of the population may be asymptomatic of Covid-19. That’s a large portion of the population that can at different times carry the virus without even knowing, potentially spreading it on to others.
Research also shows that 60 percent of Covid-19 infections are asymptomatic. While that points to broader communal immunity, it puts the plight of symptomatic people into focus.
There’s the risk that people may get complacent with Covid-19 mitigation measures, placing the unvaccinated and other vulnerable groups in danger.
As one study found, viral loads in asymptomatic people are similar to those of symptomatic people. So, we cannot afford to drop the ball on testing as a mitigation measure.
What is the Difference Between People Who Have Asymptomatic or Pre-symptomatic COVID-19?
The absence of symptoms at the time of testing does not mean you are asymptomatic. You could be pre-symptomatic, which means you do not yet show symptoms. The symptoms may develop later.
Covid-19 symptoms typically start to show after 2 days, with the virus’ incubation period lasting up to 14 days. Those first 48 hours when one is not showing signs of infection is when they are most contagious. The risk is they won’t be minded to curb behaviors they would avoid if they knew they were infected.
As can an asymptomatic person, pre-symptomatic people can spread the virus to others. So, if asymptomatic people can transmit the virus that causes Covid-19 to others and they are as many as studies have shown, isn’t it critical that they are regularly tested?
What is Asymptomatic Covid Testing?
Asymptomatic Covid-19 testing is testing that is done to see if a person that does not show symptoms of the virus has the infection. Even though there’s debate and shifting positions, including by the CDC in the USA, this testing is important for several reasons.
The main role of testing is to inform the individual of their current health status pertaining to Covid-19. Once a person has this information, they can make better decisions about their health.
Testing people at scale on the other hand helps health authorities get a picture of how many people currently carry the virus. By further processing the data, they can also identify outbreak areas, where urgent interventions may be necessary.
Testing is also essential for contact tracing. Without isolating infected people, it is difficult to stop infections before they happen. An infected person’s recent contacts may not know they have been exposed until after they have already passed the virus to others.
On the whole, asymptomatic Covid testing is crucial for preventing the risk of unknowingly spreading to vulnerable groups like the elderly. Testing, therefore, remains an effective tool for saving lives and controlling the spread of Covid.
When Should an Asymptomatic Person Get Tested?
As with all things Covid-19, there’s debate on whether asymptomatic people need to get tested regularly. Some have even gone on to say that asymptomatic people don’t need to get tested.
Health experts, however, prefer to take a more cautious approach where people understand the transmission risk they pose to others if they are asymptomatic carriers of the virus. Under pressure from experts, the CDC even had to walk back from guidance where they had excluded people who did not have symptoms.
While Covid-19 testing is most accurate for people who have shown symptoms and is most effective as a mitigation measure when conducted for people who have recently been exposed, there are instances where asymptomatic people should get tested.
For example, if you intend to travel or visit people more vulnerable to severe illness, you can better protect them by knowing your status. You should postpone your visit until the infection clears.
Asymptomatic testing can also help protect unvaccinated children. This is most important for asymptomatic people who have been exposed. In fact, anyone who suspects exposure must consider getting tested.
It is also responsible behaviour to get tested before attending an event like a wedding where a lot of people will be in attendance. You would assume this should be encouraged more for asymptomatic people who may be unknown carriers right at the time of the event.
Does Ontario Currently Support Asymptomatic Testing?
The province of Ontario no longer recommends asymptomatic testing unless it is for high-risk contacts and people in confirmed or suspected high-risk settings. This guidance is consistent with those currently in force in other provinces in Canada.
Most mask mandates in Ontario are also expiring on June 11 except for those in long-term care and retirement homes. However, some experts say some of the mask mandates should have remained in place for a while longer. Some hospitals have also decided to still maintain their mask mandates.
The main reason for excluding asymptomatic people from state-assisted testing programs in particular is more a desire to allocate resources where they have the most impact.
It is not to say that asymptomatic testing, or wearing masks, is not an effective Covid-19 mitigation measure. In many ways, the authorities are simply bowing down to pressure to ‘get back to normal’ and allow the economy to recover.
Manitoba, for example, while no longer supporting asymptomatic vaccination, recommends those visiting First Nations areas to get tested first as people there have shown severe illnesses and at younger ages when infected with Covid. Ontario itself recommends that those that feel the need to continue wearing masks.
As for asymptomatic testing, negative results are now generally seen as not informative since a person can test positive any day within the virus’s 14-day incubation period. False-negative results can also encourage a lax approach toward infection prevention in people who may be carrying the virus.
Are Antigen Tests Reliable for Asymptomatic People?
All Covid-19 tests that are currently available are not 100% accurate. That said, it has been known for a while now that antigen tests are less reliable than real-time reverse transcription-polymerase chain reaction (RT-PCR) tests.
Antigen tests are more sensitive when testing symptomatic people who are advised to test again after a day if negative. If the negative result is maintained, you must get a confirmatory PCR test. Asymptomatic people on the other hand must get a confirmatory PCR test if an antigen test shows they are positive for Covid-19.
Due to their lack of sensitivity for asymptomatic testing, antigen tests are best used for screening purposes only. They are much cheaper, far more accessible, and produce results much faster than PCR tests that can only be processed in a lab setting and which are sometimes prioritized for symptomatic people.
There is certainly less harm in taking the less reliable antigen test after you have been exposed than not testing at all because you can’t get an appointment for a PCR or wait the days it can take to return a result.
The truth is that where an asymptomatic person suspects they have been exposed to Covid testing alone is not enough to mitigate further spread. There are other behaviours they must adopt and steps they must take to break the chain of transmission.
The current guidance for asymptomatic people who are vaccinated but have recently been exposed and don’t live with the positive person is to avoid visiting high-risk areas/persons and instead self-monitor for a period of 10 days.
Can a Vaccinated Person Still Get Infected With Covid-19?
Vaccinated people, including those who are asymptomatic, can still get infected with Covid-19. But they are less likely to catch the virus than unvaccinated people. Unless they are immunocompromised, it is also unlikely that a vaccinated person will fall severely ill.
With Covid-19, we are still some way off and may not ever get to the point of sterilizing immunity where a vaccine can stop a virus from establishing an infection in an exposed person.
Where we are at with the Covid pandemic is ‘effective immunity’ where a vaccinated person isn’t fully protected from infection but is largely safe from severe illness.
Vaccination prepares your body to better deal with a virus should you get infected. The virus clears faster, which when added to the reduced chance of illness significantly improves outcomes.
Can Vaccinated People Transmit Covid to Others?
If infected, vaccinated people can be infectious. Even though the chances are far reduced when compared to unvaccinated people, vaccinated people can pass the Covid-19 virus to others.
Vaccination blunts the virus’ potency and ability to rapidly replicate. As a result, vaccinated people will have a low viral load at the peak of infection. This is also why the virus clears faster in vaccinated people.
The viral load, especially in the case of the Delta variant, can be so low that the chance you can transmit the virus to others is almost entirely removed. Given that, is it necessary for vaccinated people to get tested for Covid?
Should Vaccinated People Get Tested For Covid?
You don’t need to get tested for Covid if you are vaccinated and are not experiencing any symptoms. There are high chances that you will test negative, which will not be informative at all.
It is a little different however if you are vaccinated but are experiencing symptoms that are consistent with Covid. Even when the symptoms are mild, you must get tested and confirm whether you are indeed infected.
The reason you must get tested is there is a risk that you are infectious and may spread the virus to vulnerable people like the elderly, especially now that mask mandates are expiring.
In the case that you are vaccinated and have been infected, which is called a breakthrough infection, you may indeed be safe from severe illness, but those you may infect may not be.
If you suspect exposure and are experiencing symptoms, order a rapid antigen test and self-test at home if you are away from a health facility. If you test positive, isolate yourself from vulnerable members of your family until a negative test confirms the virus has cleared.
So, Should Asymptomatic People Get Tested for Covid?
From the available research and obtaining guidance from health authorities, whether asymptomatic people should test for Covid-19 depends on the circumstances.
Asymptomatic people should get tested if they have recently been exposed and if they are travelling or will be attending an event where a lot of people will be gathering. Testing in this regard is strictly to protect others, particularly the unvaccinated and the immunocompromised.
PCR tests are the most recommended for asymptomatic people who feel they must confirm their Covid-19 status. That said, antigen tests are still useful for people who can’t access lab-based PCR testing, even though those rapid tests are less accurate in the absence of symptoms.