Charting a Coronavirus An infection – The New York Instances

Charting a Coronavirus Infection - The New York Times

After months of downplaying the threat of the Covid-19 pandemic, President Trump announced early Friday morning that he and first lady Melania Trump had tested positive for the coronavirus. He was hospitalized at Walter Reed National Military Medical Center and had mild to moderate symptoms such as fever, cough, and congestion. He was reportedly low in blood oxygen at least twice on Friday and Saturday.

It is too early to tell whether his illness will follow a typical course or how severe his symptoms may become. And since millions of people around the world are sick, no single schedule can capture the range of Covid cases. However, months of data have helped scientists figure out the general portrait of a symptomatic coronavirus case.

Exposure and incubation

The time between initial exposure to the virus and the onset of symptoms is known as Incubation period. This period is usually four to five days, but can be up to 14 days or, in rare cases, even longer.

It remains unclear who infected Mr Trump, although there are plenty of potential candidates, some of whom gathered with the president or traveled with him to crowded campaign events on September 26 during the White House event for Judge Amy Coney Barrett.

Symptoms and recovery

Most people who get Covid recover within a few weeks and don't need hospitalization. However, resolving severe cases can take much longer. And a growing cohort of coronavirus survivors known as long-distance drivers have reported symptoms and side effects – including fatigue, memory problems, and heart problems – that can last for months.

People who develop severe cases of Covid are usually hospitalized within two weeks of symptoms appearing. However, many of the factors that catapult certain people into severe forms of the disease remain a scientific mystery. Scientists know that people who are male, older and obese – all descriptors from President Trump – are at higher risk for more serious effects from Covid.

Viral load

After an initial exposure, the number of virus particles in a person's body or Viral load, takes time to build up as the pathogen infiltrates cells and copies itself repeatedly. Mathematical models indicate that viral loads tend to peak before symptoms appear, if they occur at all, and decrease fairly quickly in the days following the first signs of illness.

Experts have said that people are more likely to be contagious when their viral load is high. In this case, the window of highest infectivity can be only a few days long, beginning a day or two before symptoms appear and closing within a week afterwards.

It also means that people in what is known as the presymptomatic stage can be highly contagious in the days before symptoms develop. Separately, asymptomatic carriers of the coronavirus have also been repeatedly identified as a source of transmission events, although less is known about how the virus behaves in such people's bodies.

If Mr Trump's symptoms appeared on Wednesday or Thursday, he may have exposed several people in the days before. It is now most likely contagious. In a series of tweets early Friday morning, the president confirmed that he and Ms. Trump would isolate themselves – a move that quickly canceled several events in the tense run-up to the November 3 election. Mr. Trump was later taken to Walter Reed for a stay of several days. He received an experimental antibody treatment developed by drug maker Regeneron, an antiviral drug called remdesivir and the steroid dexamethasone.

Testing for the virus

The White House has been scrutinizing people who come into close contact with Mr. Trump for months. Many of these screenings are Rapid testsand delivers actionable results in minutes without sending samples to a laboratory. This speed and convenience can come at the cost of accuracy: rapid tests detect worse viral loads and newer infections and are more likely to produce false negative or false positive results. Some experts argue that true positive results from rapid tests could coincide with the period when people are most contagious, although this has not yet been confirmed.

Rapid tests like the much discussed Abbott ID Now and BinaxNOW received an emergency F.D.A. green light only for sick people who are within seven days of the onset of symptoms. Use in people who do not feel sick is considered off-label, and negative results from such tests cannot rule out infection or contagion.

People with known exposure to an infected person – like Mr. Trump – or who have already developed symptoms, may need to do a more sensitive test. Experts often recommend laboratory tests based on a technique called P.C.R. (Polymerase chain reaction) which can detect very small amounts of the virus but usually takes several hours to run on sophisticated, expensive machines.

Because a P.C.R. The test is more sensitive to low viral loads and may be able to detect coronavirus infection very early. However, the diagnostic test can also pick up harmless parts of the virus that remain in the body after symptoms have subsided and possibly after a person has stopped being contagious.

Antibodies are produced by the body in response to an invading pathogen, starting about a week after infection, and can remain in the blood for months. Another type of test called a serology test looks for these antibodies instead of the virus. Experts don't consider antibody testing a reliable way to determine if a person is harboring the coronavirus.

Prevent infection

Because the virus can be transmitted by people who feel healthy, experts have emphasized the importance of taking several public health measures to combat its spread. While no single tactic can provide complete protection, the combination of actions such as wearing a mask, physical distancing, hand washing, and avoiding crowded rooms quickly reduces risk.

Mask and

physical distance

Wear mask

and distancing

Masks and face coverings covering the nose and mouth can block much of transmission and appear to be particularly effective at transmitting outbound viruses from infected people. However, there is evidence to suggest that masks can also thwart a percentage of incoming pathogens, even if they don't make the wearer immune to infection.

Mr Trump has repeatedly withdrawn masks for much of the pandemic. On Tuesday night during the debate, he mocked former Vice President Joseph R. Biden Jr. for his strict commitment to cover and physical distancing.

Infected people can also reduce the chances of getting the virus transmitted by isolating themselves for at least 10 days after symptoms appear, as long as they continue to improve. Those who have been exposed to someone with a known case of the coronavirus should be quarantined for two weeks and seek a test. Up to 40 percent of infections may be symptomatic, although some estimates were even higher.

Based on data obtained from other respiratory viruses, the researchers believe that there is likely a minimal infectious dose for the coronavirus or the lowest number of virus particles necessary to establish an infection. This number will most likely vary from person to person, and there is still no precise data on what a typical dose might look like.

The Centers for Disease Control and Prevention note that people with Covid are unlikely to be infectious for more than 10 to 20 days after their symptoms began.

Chasing the coronavirus

Sources: Centers for Disease Control and Prevention; New England Journal of Medicine; Susan Butler-Wu, University of Southern California; Daniel Larremore, University of Colorado, Boulder; Brandon Ogbunu, Yale University; Saskia Popescu, George Mason University.


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