Covid-19 instances were initially identified in the United States more than three years ago. And, while President Joe Biden stated this week that the state of national emergency surrounding Covid-19 will be lifted, this does not imply the pandemic is finished.
Despite the fact that much is now known about this coronavirus, many concerns remain, particularly as the virus evolves and infects humans on a broad scale. According to the Centers for Disease Control and Prevention, almost 280,000 new coronavirus infections were detected in the previous week. Given the number of home tests not included in the official figure, this is probably definitely an undercount.
A common query from CNN readers and viewers is what it means if someone has Covid-19 symptoms but tests negative for the virus, particularly if they have been exposed. What causes this? Should they retest, and when should they do so? Are there any further tests they should receive, such as those for other viruses? How can someone tell whether they’ve used Covid-19 before?
I chatted with CNN medical analyst Dr. Leana Wen, an emergency physician and professor of health policy and management at the George Washington University Milken Institute School of Public Health, to get answers to these issues. She has also written “Lifelines: A Doctor’s Journey in the Fight for Public Health.”
Many people assume they have Covid-19 symptoms but test negative. What causes this?
Leana Wen, Ph.D.: There are various options. First, Covid-19 often mimics other viral infections. Fever, cough, runny nose, headache or body pains, sore throat, and diarrhea are all common symptoms. These are symptoms that are also found with other viral diseases, such as influenza and adenovirus. It’s conceivable that the symptoms you’re interpreting as signs of a Covid-19 infection are really caused by another virus.
Second, you may be testing too soon after being infected with Covid; there may not be enough virus to provide a good result. In most cases, symptoms and/or a positive result appear at least two days following exposure. However, many times there isn’t enough virus to cause a positive test until at least five days following exposure. This is why it is critical to repeat testing, especially if you are using home quick antigen tests.
Third, the test might result in a false negative. Antigen testing performed at home is less reliable than PCR tests. If you have a high risk of getting Covid-19 — for example, if you were exposed to someone who had the coronavirus and now have symptoms but a home test comes back negative — you should have a PCR test.
If someone is exposed to another person who has Covid-19, when and with what test should they be tested?
According to the CDC, if you were exposed to someone who has Covid-19, you should wait at least five days before getting tested. At this time, an antigen test or a PCR test might be used. However, because symptoms might still emerge after five days, the CDC recommends wearing a mask in public indoor locations for a total of ten days. You should also keep an eye on your symptoms; if you develop any, even after five days, you should be tested again.
What if you’ve had direct contacts, such as with a partner with Covid-19, and experience symptoms, but the test comes back negative after five days?
I’d consider taking another fast antigen test the next day if you took one the day before. It’s likely that your viral load was insufficient the first time. (This is also the advice given by the Food and Drug Administration in the United States.)
If the repeat test is still negative and you need to know whether you have Covid-19, you might have a PCR test. The PCR test is more accurate, however, it does pick up virus leftovers. That suggests that if it’s positive, you may have recently recovered from Covid-19.
If all of these tests come back negative, you may have a separate viral disease and should continue to wear a mask in public for the next 10 days. Also, be cautious around vulnerable people when you are symptomatic, even if it is not caused by Covid-19. If you have plans to visit your elderly aunt in a nursing facility, for example, or to host dinner with an immunocompromised visitor, you should postpone them until your symptoms have subsided and your 10-day quarantine period has ended.
Should you be tested for other viruses if your Covid-19 test is negative?
It depends on the situation. If you are typically healthy and have just minor symptoms, testing is probably not necessary. Use symptomatic treatment, which means drinking plenty of fluids, resting, and using over-the-counter painkillers such as acetaminophen or ibuprofen as needed.
You may be especially concerned about influenza if you have underlying medical issues. There are antiviral medicines available, and you should talk to your doctor about flu testing and if you qualify for them.
Some doctors’ offices now routinely test for Covid-19, influenza, and respiratory syncytial virus (RSV). When in doubt, consult your doctor. Also, if you experience increasing or particularly alarming symptoms, such as shortness of breath, chest discomfort, or an inability to keep fluids down, contact your doctor.
How can someone tell whether they’ve previously been exposed to Covid-19?
Wen: Commercial laboratories such as Quest Diagnostics and LabCorp offer an antibody blood test for the SARS-CoV-2 Nucleocapsid. This explicitly searches for previous infections.
If it’s positive, it suggests you had Covid-19 at some point. It does not specify when. So, if you want to know if a recent round of symptoms was caused by the coronavirus, this test won’t assist. Remember that just because you’ve had Covid-19 before doesn’t guarantee you won’t feel sick from it again.
Erin Balsa is a highly skilled and knowledgeable health journalist with a passion for educating the public on important health and wellness topics. With extensive experience in both traditional and digital media, Erin has established herself as a trusted voice in the field.