For 10 months you have been hearing about how to avoid COVID-19 and what to do if you are infected.
Yet now – as the holidays increase the desire and danger of close contact – confusion seems to be the one thing that is growing faster than the pandemic. We’ve heard it all through Curious Philly, where readers ask questions and our reporters seek answers. Hundreds of people have written to ask how to quarantine, what isolation means, how to safely distance themselves socially, when they should wear masks and more.
This confusion is understandable. Public health authorities must change their advice as we learn more about the virus, and the advice cannot cover all scenarios. Some of the recommendations are unrealistic, given the need, for example, to earn a living. Plus, applying jargon-filled public health advice to real-life situations can be like taking a conditional reasoning test.
Consider the updated definition of “close contact” from the United States Centers for Disease Control and Prevention: “Someone who has been within 6 feet of an infected person for a cumulative total of 15 minutes or more on a period of 24 hours starting from 2 days before the onset of the disease. (or, for asymptomatic patients, 2 days before collection of the test sample) until the patient is isolated.
It’s understood? To clear things up (at least a little), let’s review some principles, definitions, and previous pandemic episodes of Curious Philly.
In March, diagnostic tests were largely unavailable and the virus was believed to be spread through cough or sneeze droplets that quickly fall to the ground.
At the time, the CDC’s advice was simple: If you spend at least 15 minutes within 6 feet of an infected person (close contact), stay home for 14 days (quarantine) as it can take that long. after exposure to develop symptoms (the incubation period of the virus). If you develop symptoms at home, stay away from household members (self-isolating).
The latest expert advice is more complicated because, well, the coronavirus is more complicated.
READ MORE: Ask Us a Question Via Curious Philly
The good news: the exterior drivetrain is unusual. Presumably, this is why the protests and civil unrest in the spring did not cause a sharp increase in the number of cases. And fears that the germ could be passed on to someone who has touched a contaminated surface (a fomite) has also been shown to be exaggerated, although frequent hand washing couldn’t hurt. (Go ahead with Christmas gift and food swaps that involve outdoor drop-offs.)
The bad news: Assumptions about big droplets and social distancing have turned out to be simplistic.
The germ can be spread by an infected person – including someone who has no symptoms or who does not yet have them – in microscopic particles released into the air when speaking, singing, or simply exhaling. The virus can float around a room, carried by drafts or drafts, and be inhaled by an unlucky bystander.
And while most people who develop symptoms do so four or five days after exposure to the virus, research has highlighted the relationship between exposure, symptoms, and contagiousness. The virus takes time to replicate and build up in the body, so the window where you are most contagious appears to be a day or two before symptoms appear, and about a week after.
It also has implications for molecular diagnostic testing. Studies suggest that in the first four days of infection, molecular tests miss up to two-thirds of infections. After the onset of symptoms, the rate drops to around 20 percent.
All of this helps explain why the CDC’s updated definition of “close contact,” cited above, is so complicated. It takes into account the risks of multiple brief exposures, whether the infected person had symptoms and whether the infection has been confirmed by tests.
READ MORE: How Long Can You Be Safe With Someone With Coronavirus? It is complicated
Quarantine guidelines have also evolved, as staying home for 14 days is often impractical and generally excessive.
Now the CDC outlines the options: End quarantine after 10 days without diagnostic testing if you have not had any symptoms. The risk of accidental transmission is low, in the order of 1 to 10%.
READ MORE: These are the current guidelines for the Philadelphia Coronavirus
If you test negative, the quarantine may end after seven days. With this strategy, the risk of transmission is 5% to 12%.
Alas, there are many scenarios that the CDC and other authorities don’t explicitly address, so you just need to use your judgment.
For example, suppose you live with someone – say, a child or a partner – who has been in close contact with an infected person. Should we also quarantine? Experts say quarantine is not necessary for people with such “secondary exposure” unless the person who has had close contact is positive.
Another and if this Curious Philly addressed the question of whether an infected person can visit an infected friend to spend time together.
“The safest thing is to stay at home,” Patricia Henwood, an emergency physician at Sidney Kimmel Medical College at Thomas Jefferson University, told journalist Grace Dickinson. “We want people to avoid public transportation or anything that could put others at risk. “