COVID Reinfections FAQ

The first time our bodies encounter a new virus we’ve never seen before, we rely on something called our innate immune system to fight it off. It’s a non-specific response that triggers inflammation pathways, among other processes, with the end goal of resolving the infection. However, our adaptive immune system is able to create a memory of this first infection so that the next time we encounter the same virus, antibodies are able to quickly recognize the threat and mount a specific and efficient immune response against it, oftentimes before we even experience any symptoms. Vaccines are boosters of the adaptive immune system, in the sense that they safely evoke immune memory against infections without evoking disease associated with the infection itself.

Immune memory was first described thousands of years ago, during the Plague of Athens, when it was written that those who became ill but survived the first wave of the plague could care for people who became ill in subsequent waves without becoming ill themselves. Thankfully, in more modern times, we’ve learned to harness the power of immune memory using vaccines, so we don’t even have to become ill to develop immunity to some very dangerous diseases.

Can you get COVID more than once?

Yes, you can absolutely get COVID more than once, and reinfections are becoming increasingly common.

Unfortunately, with the rapid appearances of novel viral strains, COVID is escaping our immune system memory and unlike with many other viruses, we aren’t fully immune after infection or vaccination.

Can you get COVID more than once even if you’ve been vaccinated and boosted?

Yes, unfortunately, even people who have been vaccinated and boosted can get COVID, and can get it more than once. You can also spread COVID, even if you’ve been vaccinated and boosted.

The vaccines did an excellent job protecting against infection from the first variant of the virus that we experienced during the spring of 2020. Vaccines reduced the chance that you’d catch the virus during the time, experience any symptoms at all, and even reduced the chance you’d spread COVID.

Then in the Delta wave, vaccines plus booster shots provided good protection from symptomatic illness from COVID.

But now we’re in the Omicron era and it’s pretty common to become ill with COVID even if you’ve been vaccinated and boosted on schedule. Vaccines still provide a degree of protection from severe disease which is obviously important, but they currently do not prevent us from experiencing symptoms of COVID, spreading COVID to others, or developing Long COVID.

Why do COVID reinfections happen? Shouldn’t we have natural immunity to the virus after an infection? How is COVID escaping our immune memory?

The main problem is that COVID is evolving to escape our immune memory. The virus has a component called the spike protein, and this spike protein is the key to invading the cells in our bodies.

Omicron variants have mutations in the spike protein that increase the virus’ ability to invade our cells while making it less recognizable to our immune system. You can imagine that our immune system’s memory cells are like security guards to our body and are trained to recognize a specific person. Now imagine that person grows a beard, puts on a wig, hat and sunglasses and at the same time gets better at sneaking past the security guards. Metaphorically speaking, of course, this is what COVID is doing very well–the virus is circulating at very high levels in our society and because of this, it has plenty of chances to mutate into variants that are better able to escape our immune memories.

https://doi.org/10.1038/s41586-022-04980-y

What is herd immunity? Can we achieve herd immunity from COVID? How does this compare to other diseases?

Herd immunity is the idea that an indirect protection from infection (and thus illness) is granted to vulnerable individuals in a population when a sufficient number of people are immune, stopping chains of disease transmission. Herd immunity can be achieved either through infection or through vaccination.

Immunocompromised people who cannot get vaccinated can remain protected when the majority of the population is vaccinated.

In the beginning of the pandemic, many politicians thought that once enough people contracted and recovered from COVID, enough people would gain immunity and that would stop COVID. Unfortunately, COVID is not behaving that way and aside from natural herd immunity being impossible to achieve, there are risks of death and Long COVID with every infection. Another consequence of attempting to achieve herd immunity when it is not possible with COVID is the danger of increasing all causes of mortality due to the burden on healthcare systems.

We’ve stopped a lot of other dangerous diseases with herd immunity and vaccination in the past. This would include measles, mumps, whooping cough, and diphtheria, among others, however, we don’t have herd immunity to the common cold caused by four circulating coronaviruses despite being repeatedly exposed to these viruses. These coronaviruses that cause the common cold are cousins to COVID-19, and, like COVID-19, they dodge our immune defenses and we can be infected and reinfected with them time and again. So, not every virus can be stopped through herd immunity following natural infection, and unfortunately for us, the coronavirus family seems pretty adept at evading our immune systems.

How common is it to get COVID more than once?

Reinfections are not being tracked systemically but appear to be fairly common.

Are COVID reinfections more mild than the first infection?

COVID is a potentially severe virus that can worsen pre-existing conditions or leave people with new health conditions like Long COVID, which can include problems such as vascular, neurological and organ damage to new autoimmune diseases. If someone develops these conditions following a first COVID infection, a second COVID infection could impact them quite severely. Reinfections can also increase the risk of having at least one COVID-related health sequelae, including cardiovascular, gastrointestinal, kidney and neurological disorders.

A study published back in December of 2020 showed that second infections with COVID could be more serious than the first infections. At that point of the pandemic, reinfections, although they could be serious, were rare, both because we were taking collective measures as a society to mitigate the spread of COVID, and because we didn’t yet have the extremely contagious, immune evasive variants that we’re dealing with today. The early data was showing that reinfections were rare but that previous infections with the virus didn’t do a great job at lessening the severity of the reinfection.

The landscape today looks different. We have vaccinations and boosters that absolutely mitigate the severity of infections and we’re in the Omicron era. We know the Omicron variants are less likely to lead to hospitalization and death than the viral variants that came before, but neither risks are currently negligible. Today a lot of pundits and public health professionals are saying that reinfections are generally milder than the first infection, but it’s still an open question as to whether this is due to milder variants currently circulating, or due to the immunity from previous infections plus vaccinations, or whether all of these are contributing factors. Because Long COVID can develop even after a mild or asymptomatic case of COVID, reinfections should be prevented. COVID reinfections are not always more mild than the first infection.

Reinfection With SARS-CoV-2: Implications for Vaccines Jeffrey I Cohen, Peter D Burbelo Clinical Infectious Diseases, Volume 73, Issue 11, 1 December 2021, Pages e4223–e4228, https://doi-org.proxy1.lib.uwo.ca/10.1093/cid/ciaa1866 Published: 18 December 2020
Shaheen et al.

Are there long-term consequences of multiple COVID reinfections?

Yes, for some people. A large study was recently conducted using data from the United States VA hospital system. The VA (Veteran’s Affairs), system provides healthcare to many of America’s veterans. This study looked at the health records of more than 5 million people, including more than 40,000 people who had been reinfected with COVID, sometimes multiple times. They found that the people who were reinfected had twice the risk of dying of any cause, as well as twice the risk of heart and lung problems, as compared to the group that had only been infected one time and with each reinfection, the risks grew larger. The reinfected population also had higher risks of Long COVID symptoms like fatigue and digestive issues.

https://www.webmd.com/lung/news/20220707/each-covid-19-reinfection-increases-health-risks#:~:text=Among%20those%20with%20reinfection%2C%20about,of%20dying%20from%20any%20cause.

Are kids at risk for COVID reinfection?

Yes, children are at risk for reinfection from COVID. Because most schools have dropped COVID mitigation measures, kids are frequently becoming reinfected, sometimes within quite a short time frame– only a couple of months, and sometimes within only a matter of weeks.

What is the risk of developing Long COVID from COVID reinfections as opposed to the first infection? If I had COVID once and did not develop Long COVID, am I in the clear?

We don’t have data on the risks of this happening yet. It has certainly happened to some people– they recovered successfully from their first bout with the virus but a subsequent infection left them struggling with symptoms of Long COVID. Additionally, as much as half of people with Long COVID develop myalgic encephalomyelitis (ME), a debilitating neuro-immune illness. About 2/3 of ME cases develop after an infection. While it’s great if you recover quickly and fully from a first bout of COVID, there is no guarantee you will do so with subsequent infections as well.

Do masks harm natural immunity by preventing exposure to viruses?

There is no evidence that masks have a bad impact on our immune systems and long-term health. As a matter of fact, people in Japan routinely wear face masks to prevent the spread of diseases and have done so before COVID and they have the longest life expectancy of any country in the world.

We have a pretty pervasive myth in America that if it doesn’t kill you, it makes you stronger, and that’s just not the case with really dangerous diseases, including not only COVID, but other viruses like the measles as well. These viruses actually weaken our immune systems, and so it’s worth doing what we can to protect ourselves and those around us, and that includes masking to prevent infection.

https://www.bbc.com/future/article/20211112-the-people-with-immune-amnesia#:~:text=Essentially%2C%20when%20you’re%20infected,is%20near%2Dtotal%20and%20permanent.

https://www.medrxiv.org/content/10.1101/2021.07.30.21261234v1.full

What is the ‘multiple hit’ theory of post-infectious illness and how does this apply to Long COVID?

The multi-hit hypothesis of chronic disease speculates that genetic or environmental factors can ‘prime the pump’, so to speak, to make someone more vulnerable to developing a post-infectious illness like Long COVID. These environmental factors can include anything that places significant stress on the body, including past exposures to other viruses. We don’t know yet whether COVID reinfection can in and of itself be that ‘multiple hit’ that contributes to Long COVID, but the large VA study suggests that it could be.

I am hearing COVID can reactivate viruses. What does that mean? What’s the difference between reinfection and reactivation?

A reinfection is a new infection with the same virus, which is what’s happening with COVID. A reactivation is when a virus lies dormant in the body after infection and people can become symptomatic again, usually after a certain trigger. And COVID can be that trigger, causing latent viruses in the body to become active again.

The two most common viruses that are reported being reactivated following COVID are mono, or Epstein-Barr, and herpes zoster, which causes shingles. Some people who have had a COVID infection, and are recovering suddenly are faced with symptoms of mono or shingles. These are both viruses that lay dormant in the body. After we’re infected with mono or chicken pox, we may never clear these viruses from our bodies. When they’re reactivated, they lead to symptoms of that disease. It’s a topic of active research to determine how much viral reactivation contributes to Long COVID.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8233978/

Is there anything we can do to prevent COVID reinfections?

Yes, absolutely. For now what we need to do collectively is to take actions to slow the spread of the virus. This includes the tried and true methods we all used in the beginning of the pandemic, like social distancing, masking, testing, and quarantining when we’re sick. Because the Omicron family of COVID variants is so contagious, it’s worth investing in higher quality masks, like N95s or KN95s, and for kids KF94s, especially if you’re in an indoor situation where other people aren’t wearing masks. We also need to be urgently pushing for better ventilation in indoor public spaces like schools, and holding gatherings outside whenever feasible. While it’s still possible to contract Omicron outdoors, the likelihood of transmission is very much decreased.

Will we have to mask forever?

We hope not but we need more tools to fight this virus before we can stop masking routinely and we should push our elected officials to invest in developing those tools. For instance, there are pan-coronavirus vaccines being researched that should work better against the multiple variants of COVID-19, as well as nasal vaccines that could do a better job at creating mucosal immunity, which could better protect us from infection. However, the development of this new generation of vaccines lacks the resources and urgency that was put into Operation Warp Speed to develop the first generation of COVID vaccinations.

https://www.science.org/content/article/why-efforts-make-better-more-universal-coronavirus-vaccines-are-struggling

Can you tell me more about what Patient-Led is doing to study COVID reinfections?

We’ll be conducting survey-based research in the patient community. We’ve recently received funding from Balvi, and are in the study design phase. What questions surrounding reinfection are the most important to you, your family and your community? What do you think we should be focusing on? We would love to hear from you.