The CDC Changes Its COVID Policy

Thanks to Ed M.

The CDC press release stated that those with COVID can return to normal activities if symptoms are improving and fever, if present, has been gone for at least 24 hours. To make sense of this recommendation, we need to understand that COVID occurs in two stages. In the first stage, the virus is dominant. In the second stage, the immune system takes over.

The Virus Stage: SARS-CoV-2 virus enters the body in tiny droplets that spread from the nose and mouth by someone who is infected. The virus then attaches to and enters cells that line the nose, throat, windpipe, breathing tubes (bronchi), and, in the most severe cases, lungs. After the virus enters cells, it begins to reproduce itself. Whereas one virus particle might enter a cell, about 100 leave the cell before killing it. Hundreds of viruses become thousands of viruses that become millions of viruses. At this point, most people don’t have any symptoms. But they are highly contagious. So, when people recently infected talk, laugh, sneeze, or sing, virus-containing droplets can be shared. As is true for many infectious diseases, people are most contagious a day or two before symptoms begin, when virus reproduction is at its peak.

The Immune Response Stage: After a few days, the body’s immune system begins to respond. B cells make antibodies and helper T cells assist. Cytotoxic T cells kill virus infected cells. The war is on. Although it might seem surprising, symptoms don’t become obvious until the immune system kicks in, because it’s the immune system—not the virus alone—that causes them. Once the immune system begins to fight back, viral reproduction becomes a smaller part of the disease process.

It would make sense that as symptoms improve—or, said another way, that the immune system abates—that people who are infected will be far less likely to shed virus and infect others. The CDC, as an extra measure of caution, argued that people with resolving symptoms could still reasonably wear a mask for an additional five days when in public. 

Here’s another way of approaching this. If you have symptoms of a respiratory viral infection and are in a high-risk group, test for COVID. If you have COVID, take an antiviral medicine early in the illness. If you aren’t in a high-risk group, don’t test for COVID. Just assume that you have COVID or one of the other respiratory viruses that routinely cause thousands of people to be hospitalized and die every year. Both groups should stay home until symptoms improve. If you can’t stay home, where a mask in public until your symptoms improve.

During the pandemic, many people felt that if they had respiratory symptoms but tested negative for COVID, they could go about their daily activities as before, comfortable that they weren’t spreading a harmful virus. This didn’t make any sense. Other winter respiratory viruses are also deadly, especially for the very young, very old, or people with chronic diseases or weakened immune systems. For example, every year in the United States:

· Influenza causes 140,000 to 800,000 hospitalizations and 12,000 to 60,000 deaths—100-200 of those deaths occur in children.

· Respiratory syncytial virus (RSV) causes about 150,000 hospitalizations in children and 100 to 300 deaths. In the elderly, RSV causes between 60,000 to 120,000 hospitalizations and 10,000 to 14,000 deaths.

· Parainfluenza virus causes about 50,000 hospitalizations in children.  

In other words, you don’t have to have COVID to be sick or to die or to transmit a virus that could harm or kill others. This approach, which is more respectful of others, would mean a dramatic change from what we have been doing. But it makes more sense than treating COVID differently from these other infections