Can You Catch COVID-19 Twice?
You are probably tired of hearing about the coronavirus, and it has only existed on Earth for seven months or so – as far as we know. Can people get it twice? A recent Vox case suggests that the answer may be yes, but there are too many unknowns to confirm if this is true and what it means. Here are a few things to keep in mind.
Test results are not perfect
First, how do you know if a person has contracted COVID twice? In this patient’s case, they were sick with symptoms similar to COVID and tested positive; then they felt better and received two negative test results; then they got sick again and tested positive again.
All of these tests were of the PCR nasal swab type (as opposed to antibody tests, which are different ). This type of test is accurate enough if it is positive, but false negatives are fairly common. One study found that 66% of patients had a false negative outcome 21 days after symptom onset.
So it is possible (though unlikely) that the original test was false positive. There may also be a case where the patient has had a single long-term infection and the negative tests were false negative. We know that some infections can last for months . Again, this is unlikely, but definitely possible.
We need to know if these cases are rare or common.
This Vox article is about one person. Let’s say all test results were accurate and that a person has definitely contracted two separate coronavirus infections. What does this mean for all of us?
Epidemiologist Mark Lipsich tweeted that a mistake is being made in such news: “combining ‘x is possible’ with ‘x is common.’ We do not yet know if there is something unusual about this person, or if all such cases happen. all over the world and is not found.
For example, there are known cases of re-infection with measles , but measles is recognized as a disease that, as a rule, can be infected only once. His vaccine works well, and herd immunity effectively limits its spread. These reinfections are rare outbreaks that suck for the people involved, but they don’t change the overall picture of what’s happening to the general population.
However, we recognize a trend by finding a case, then another case, and then looking for others. Just a few months ago, we didn’t know if people could spread the coronavirus without symptoms. We now know that this is probably one of the main driving forces behind its spread .
Many important questions remain unanswered
Also, did this person actually get infected twice? and is he the only one? there are many other important questions that we don’t have good answers to yet. Scientists are working on them. These include:
- Does the infection confer only a short-term immunity that fades away like the coronaviruses that cause the common cold?
- Are Antibody Tests Enough to Determine Your Immunity?
- Can a vaccine provide long-term immunity even if the virus itself does not?
- Is it possible that instead of being protected, the first infection will make you more vulnerable to the second? (Another virus, dengue , works the same way.)
We still have a long way to go before we give up the idea of long-term immunity, or even short-term immunity. However, we know that natural herd immunity is not a saving grace , but a sign that we have failed to protect our society from the virus. Let’s hope for immunity, period, but let’s also hope that we will achieve this with the vaccine, and not at the expense of not being able to protect each other.