Question: I tested positive for COVID-19 a few weeks ago. I experienced some mild symptoms such as fever, cough and fatigue. But I seem to have fully recovered. Am I now immune to COVID-19 and can I go back to living a normal life – free of wearing a facemask, constant hand washing and physical distancing?
Answer: Don’t discard your facemask just yet. SARS-CoV-2, the novel coronavirus that causes COVID-19, is so new that medical experts are still trying to determine how long immunity might last following an infection.
In fact, troubling evidence suggests immunity might be very short lived in some people.
U.S. researchers recently published a case report of a Nevada man who was re-infected within six weeks of first testing positive for the virus. And for this 25-year-old patient, the second bout of the illness turned out to be worse than his original infection. This time, he had to be hospitalized and given extra oxygen because of difficulty breathing.
A few other re-infection cases have been reported from other places – including Canada.
Immunity lasting for only a few weeks is probably the exception rather than the rule, says Dr. Andrew Morris, medical director of the antimicrobial-stewardship program at Sinai Health and the University Health Network in Toronto.
After all, he notes that more than 40 million people worldwide have contracted COVID-19 and, so far, only a handful of re-infections have been identified.
“I think we can comfortably say it is extremely unlikely that someone will be re-infected in the short term. What we don’t know is the long term,” says Dr. Morris.
Will immunity last several months or a few years? Researchers just don’t have enough information to make a reliable prediction.
What can be said with some certainty is that the body’s immune system usually produces specialized cells to guard against subsequent attacks from a microbial invader.
“Like an army, there are different types of immune cells that carry out specific jobs and they all work better together,” says Rob Kozak, a scientist and clinical microbiologist at Sunnybrook Health Sciences Centre in Toronto.
For instance, antibodies will bind to the surface of a virus, marking it for elimination by other immune cells. And if the virus evades detection by the antibodies and actually enters a cell, so-called T-cells can destroy the infected cell to prevent the virus from replicating.
After an infection is over, the immune system usually develops a type of memory of the foe so that the body’s defences are primed and ready for future attacks.
Blood tests can reveal if a patient has developed antibodies to a pathogen. But in the case of COVID-19, researchers don’t know how many antibodies are needed to successfully fight off subsequent infections, says Dr. Kozak.
As a general rule, these protective antibodies tend to decline over time. We can also expect that the ability to beat back the virus will vary from person to person – depending on an individual’s genetics and overall health. Furthermore, a virus can mutate, essentially presenting as a brand new threat.
So immunity acquired through an infection isn’t a sure thing.
However, researchers are confident that they can create effective protection with a vaccine – several of which are currently under development.
“A vaccine can be formulated to enhance the immune response,” explains Dr. Kozak. He notes that adjuvants – or immunological stimulants – can be added to a vaccine so the immune system produces more antibodies and long-lasting protection.
Even so, it will likely be some months before one of the vaccine candidates clears all the safety and effectiveness tests and is ready for the general public.
In the meantime, all of us – including those who have already recovered from a bout of COVID-19 – should do our best to protect ourselves and others from infection, says Dr. Allison McGeer, an infectious diseases physician at Sinai Health.
That means wearing a facemask properly (covering the nose and mouth), frequent hand washing and keeping a safe physical distance away from others.
“I think there are a lot of people who are impatient with this advice,” says Dr. McGeer.
She readily acknowledges that some who have already been infected may be tempted to forgo such precautions because they might assume they are immune. And, unfortunately, the medical community can’t provide them with an accurate estimate of their potential risk of re-infection.
“Until we have more data, it is really hard to say anything other than you just need to be careful for now,” says Dr. McGeer.
Sunnybrook’s Patient Navigation Advisor provides advice and answers questions from patients and their families. This article was originally published on Sunnybrook’s Your Health Matters, and it is reprinted on Healthy Debate with permission. Follow Paul on Twitter @epaultaylor.
If you have a question about your doctor, hospital or how to navigate the health care system, email AskPaul@Sunnybrook.ca
The comments section is closed.
I contracted Covid 3 weeks ago, I lost sense of taste and smell for a couple of days had some stuffiness, felt some stabbing pains in body at random a few times, like a sharp tingle feeling and I was very tired at times, had a sore
throat a couple of the days, at times for 1 min or less couldn’t breathe if I was laying down. I never had a fever and took my temp. before I contracted it and after everyday since the virus was announced! I believe I have recovered. I consulted my doctor and she said to wait 14 days before getting the vaccine. I am concerned because It is already in my blood and Isn’t in the vaccine as well? I don’t want to reinfect myself and have a reaction. Not enough research has been done on this. My doctor said MOST people were fine to get the vaccine after being infected. Can I wait a month or two or should I make the apt. to get the vaccine within the next 2 weeks ?I have had reactions from vaccines a child. I have read about the T cell test ect but they don’t know how long you will be immune ect, ect, All I do is read back and forth both studies of the effects of vaccinating or not to vaccinate after having it and I don’t feel safe either way. It is causing alot of mental stress for me, not to mention that I do not trust the media or the govt. What advice can you possibly give me?
I tested positive for covid 19 4 week ago had mild symptoms like mucus in my chest no cough no fatigue no lost of taste or smell no fever, however I felt better a while then a couple a days I feel like I’m getting a sore throat could it possible be that I could still have the virus?
Mary. Thank you for your continued health care service. I’m glad you recovered and are feeling well. From a common sense point of view, the human immune system is strong for the young and weakens for most when they are elderly.
You went through the 4 stages of a viral model: Susceptible, Exposed, Infected, Recovered. For a period of times (likely years) you will not be Susceptible to this strain of virus. You will continue to be Exposed in your work environment and your body will immediately fight it off. Viruses tend to mutate over time so we cannot be sure how long you will be protected from any respiratory virus or bacteria. Your immune system is continually sensing, learning and creating anti-bodies to fight off infection.
https://www.technologyreview.com/2021/01/06/1015822/covid-19-immunity-likely-lasts-for-years/
I am healthy worker in red zone
I was infected with COVID-19 a few weeks ago have mild symptoms lost smell,test , tiredness. I was in isolated for 10 days.now I am back to work same place do you think I would not be infected again?
Mary. Thank you for your continued health care service. I’m glad you recovered and are feeling well. From a common sense point of view, the human immune system is strong for the young and weakens for most when they are elderly.
You went through the 4 stages of a viral model: Susceptible, Exposed, Infected, Recovered. For a period of times (likely years) you will not be Susceptible to this strain of virus. You will continue to be Exposed in your work environment and your body will immediately fight it off. Viruses tend to mutate over time so we cannot be sure how long you will be protected from any respiratory virus or bacteria. Your immune system is continually sensing, learning and creating anti-bodies to fight off infection.
https://www.technologyreview.com/2021/01/06/1015822/covid-19-immunity-likely-lasts-for-years/
Perhaps a rather obvious observation?
Economies can recover and life can normalise. But people don’t come back to life!
“Economies can recover”… It’s so simple isn’t it? Lol. Economies can recover over years, if not decades, if at all. A collapsed economy will cause more death and despair than this virus. 99% of people who catch it recover. End of story. End the lockdowns!!!
I and my wife were quite seriously ill and it lasted over 3 weeks and we only just avoided hospitalisation. The “long Covid” symptoms were awful and I still have some upper respiratory chest pains. Overall though we are near normal (and my wife had developed pneumonia). Blood tests show that 6 months later she still has a large number of antibodies – and I have twice as many! I think it may be due to the viral load that someone may receive in the first place. My wife’s father became infected and died within 6 days of developing symptoms. In taking care of him he accidentally dislodged my mask and coughed right in my face! I tested positive two days later, my wife the day after and so the Hellish experience began. Given that I am a scientist and my wife a doctor, we do not assume we are immune, but our se secondary immune defences MUST have been triggered. We still wear masks, wash hands, use alcohol hydrogel and keep safe distances from others. But I have little doubt we are immune to the current Covid variant, at least for the near future.
So my conclusion? If you have a strong reaction to the virus, your secondary immune system WILL be activated. Thus however will depend on viral load, age and other factors already discussed. So let’s not make assumptions. An effective vaccine is the only way out of this nightmare. Do not get infected. It has been the worst experience I and my wife have ever had. It really can kill you and quite quickly. We are in the vulnerable age group. Her father was 98 years old.
PCR testing was never designed to detect and diagnose viruses. PCR inventor Dr. Mullis said so himself recently when the COVID outbreak began. The fact is that we do not know what COVID really is. Coronaviruses have the largest genomes of all viruses, this is a fact. COVID is something that has not been really sequenced and different labs have come up with different strains. We know it causes cold-like symptoms that may progress to serious illness in some people with certain co-morbidities. Fun fact is that Influenza can progress to ARDS in some people as well, but it wasn’t ever really hyped as much as this. What PCR does is it takes some “genetic fragments” of stuff swabbed out of your nose and amplifies it many times over cycles (they say anything greater than 35 cycles is overkill) to then see what matching “sequences” can be found. However, as I mentioned we don’t really have a COVID genome sequence with enough confidence to say “hey this is COVID”. So let’s say there is a virus and it has the following genome or identifiers AABBCCDDEEFFGHABBCC only COVID would be tens of thousands of times longer. And now let’s say there is a family of these viruses and they have very similar identifiers AABBCCDDEEGHABBCC (note this one is missing the FF) and there may be several similar but slightly different identifiers in these families. Now we want to see if you have our special unique identifier. We swab you, however we very likely will never get enough genetic material in enough quantity to have the full name, we might run PCR and just get FGHA or GHAB and we multiply that and then we magically decide that you have enough of a snippet to classify you as COVID+. The thing is, the more amplifications you run the higher the chances of getting more snippets show up; so if I amplify something 10 times vs 40 times, in the 40 times I may just get enough fragments to show something. So this is where the danger of false positives comes in. If you have a sister coronavirus (ie. common flu) and I get a small sample of genome from your nose but I then put this genome in the laundry and amplify / spin it 40 x, things are going to show up that may be snippets of sister viruses but they will show up in higher frequency than someone who I only spin 10x, and I may say you have COVID. This PCR is never really a 100% accurate test like say a blood test for HIV, it just says “you have some genetic material which shows up in some coronavirus sequences and maybe even in this new coronavirus, but we spun in 40x, grew it, some stuff showed up and we will call you COVID+”. One of the problems in ONtario is that we use this very very sensitive test that runs the amplification > 35x (which is not recommended by several scientists). So the risk here is you are falsely labeled as COVID when you really have a common cold. This likely explains why 97% of people have mild cold-like symptoms in the first place. Now if it was 4 years ago and you got some sniffles / cough, would you run to your MD and beg for a test to label you, when you know that this will pass in a week or so? Were we not discouraging people from coming in with flu symptoms 2 years ago, because we cannot do anything for a virus except stay home, stay hydrated, rest etc. If you are not short of breath and dying why are you running to get tested and creating a mass hysteria? Why not stay home and treat yourself like a normal flu? Think of all the damage of the shut downs – the skyrocketing suicides (I work in a unit that has seen a drastic rise), the economic collapse that is starting and will likely result in years of financial trouble for many people, the people we lost who had delayed cancer treatments and surgeries. The people we lost who were too afraid to come to emergency and allowed their issues to worsen. Please read this and consider the facts: https://gbdeclaration.org/ Over 33,000 medical workers are asking these questions.
Guy
I lost taste and smell very quickly. Weird as it never happened with flu infections for me. Given the immediate and severe fatigue along with demonic headaches and “electric skin” pain – and that my father-in-law (who infected me) died so quickly, I knew I was infected with Covid19. Few people will have such confirmation. All you say is true and we were confused by my wife’s initial negative result. But we knew this was highly unlikely to be true! But the issue here may also be “long Covid”. Although we are near “normal” now, my wife still has rarer “fatigue bomb” incidents and I have upper respiratory aches and pains. If early treatment could reduce the incidence of such fate effects then we may avoid a time-bomb in waiting a few years down the line?
Lol. Write a longer response, professor… everyone who watches the news is an expert now. Hooray!
Great and interesting info, especially now and very actual!
The PCR test used is notorious for false negatives. People that are sick may not express enough viruses where they are swabbed to register a positive. That’s why they are swabbed in multiple places. Unfortunately, there is no easy way to swab the lungs, where it really matters. After a couple of false negatives, you are “recovered” and sent home.
Also, there are reports that people that are still recovering, but are improved, are getting kicked out of the hospital in China to make space for sicker patients. Some of these “recovered” patients relapse and get worse again.