Already had COVID-19? What to look out for, and why to wear a mask
Scientists still don’t know a lot about immunity and reinfection from SARS-CoV-2.
ST. PAUL — Since the pandemic began in March, roughly 350,000 Minnesotans have tested positive for COVID-19 and more than 300,000 have recovered enough from the coronavirus that they likely won’t pass it to others.
But that doesn’t mean they’re done with COVID-19.
It’s been less than a year since scientists first identified SARS-CoV-2, which has shaken the globe, infecting at least 64 million and killing more than 1.4 million people.
“There are so many things that we are still learning about, that are still unknown,” said Dr. Nick Lehnertz, a Minnesota Department of Health medical specialist in the infectious disease division who is studying COVID-19 and its long-term effects.
In Minnesota, the coronavirus has killed more than 3,800 people and sent another 17,600 to hospitals, including nearly 4,000 who required critical care.
Vaccines are expected to soon become available to a very limited number of medical workers and long-term care residents. In the meantime, it’s important for everyone else to understand what scientists now know about coronavirus transmission, recovery, immunity and reinfection. Here are the answers to some common questions:
How long are people contagious?
SARS-CoV-2 typically has an incubation period of between two and 14 days after a person contracts the coronavirus. Many people never experience symptoms and most are contagious before they know they are infected.
That’s why it is important to understand that a negative test one day doesn’t mean there isn’t an infection a few days later.
Lehnertz says there is also a distinction between quarantine and isolation.
Someone who is exposed to COVID-19 or suspects they are infected should quarantine themselves at home for 14 days, regardless if they have symptoms or test negative.
On the other hand, someone who tests positive for COVID-19 should isolate themselves, including from others in their household, for at least 10 days from the onset of symptoms or a positive test, preferably whichever is longer.
“Generally speaking, you are contagious up to nine days from the onset of symptoms,” Lehnertz said.
Long-term health issues
Most people who get COVID-19 are feeling better a week or two after the onset of symptoms. Yet, the virus has been known to have dramatically different effects on different people.
A small minority of people who catch the coronavirus experience symptoms, such as fatigue and body aches, for weeks or months after first getting sick. Not a lot is known about these so-called “long-haulers,” but Lehnertz says a number of clinics around the country are studying patients whose symptoms persist.
There are also a number of other health concerns that can arise in people who’ve contracted SARS-CoV-2 and recovered.
One of the best known is multi-system inflammatory syndrome, which typically appears in children, and causes different organs to become inflamed. To date, there have been 42 cases diagnosed in Minnesota and no fatalities.
There have also been shorter-term complications, including difficulty concentrating, depression, muscle pains and heart palpitations. More serious long-term impacts that have been recorded include inflammation of the heart, breathing problems and kidney injury.
Little is known about why these conditions occur and the lasting impact of contracting COVID-19. Health officials say anyone recovering from the disease should monitor other symptoms and health concerns and contact their physician.
“Everyone knows themselves,” Lehnertz said. “People will know when something is not right.”
Can people get it twice?
The simple answer is yes, but it is probably highly unlikely. The science is complicated and there’s a lot that’s still unknown.
Lehnertz says there have only been a handful of proven examples of reinfection out of 64 million known COVID-19 cases worldwide. In order to prove a reinfection, scientists need to compare both strains of the SARS-CoV-2 that infected an individual to be sure.
Viruses are constantly mutating over time and there are several identifiably different strains of COVID-19. Sequencing the DNA of two samples collected from the same person at different times is the only real way to know for sure if someone was infected twice.
“That’s the gold standard,” Lehnertz said. “That’s when we can see, yep, this is completely different.”
What’s more common, but still unlikely, is people who test positive for the same strain of the coronavirus repeatedly over a long period of time. These people shed virus fragments for weeks or months and may test positive repeatedly, but are not suspected to be transmitters after the initial contagion period.
How long does immunity last?
This is a question that will take more time to answer.
There is some evidence that people who’ve recovered from COVID-19 have virus-fighting antibodies for months. In others, the presence of antibodies begins to dwindle after a while.
Just because antibodies cannot be detected doesn’t mean the immune system will not remember COVID-19 and how to fight it.
It will likely take a number of years before scientists have a clear picture of SARS-CoV-2 immunity and how often people need to be vaccinated against it.
“When push comes to shove, we just don’t know enough about the duration of immunity and how it would affect a second infection,” Lehnertz said.
In fact, the Centers for Disease Control and Prevention say people who have recovered from a coronavirus infection may still benefit from getting vaccinated. Guidance released in late November cites all the current unknown factors about the coronavirus.
What remains unclear is when previously-infected individuals will be eligible to get vaccinated.
Masking and social distance
For the foreseeable future, health officials say everyone should wear masks, social distance, avoid crowds and stay home when they are sick because there are so many unanswered questions about COVID-19.
The biggest reason for those mitigation efforts is to protect people who haven’t gotten sick yet — especially those who are medically vulnerable.
But there’s also good reason to shield those who believe they’ve recovered from COVID-19 since there’s so much unknown about the long-term impacts.
“It’s not a huge ask to wear a mask,” Lehnertz said. “We are all in this together, right? Just wear the mask and stay 6 feet away. It’s not hard.”