COVID Crash Course: Part 1 - How You Might Get Infected And What Happens Then

Moritz Jaax

Given that vaccines are only just beginning to catch up to the novel coronavirus, we thought it would be useful if today’s post tackled the most important questions about the pandemic. This brief overview should help debunk some myths and clear up a few misunderstandings.

When the coronavirus SARS-CoV-2 arrived in March 2020, it probably completely changed your everyday life. To prevent the virus-induced disease, COVID-19, from spreading too quickly and plunging the healthcare system into chaos, strict contact restrictions were set in place to varying degrees in most states.

There has recently been some good news though - a couple of vaccines have shown promising results and public vaccine administration has begun [46] (although, for now, only in certain countries where the vaccine has been approved). Scientists around the world are working on testing and finalizing these vaccines while developing more effective testing and immunization campaigns.

In this article, we have summarized answers to important questions on the topic and presented them in an easy-to-understand form. From infection, symptoms, and possible long-term consequences of tests to protective measures such as lockdowns, hand hygiene, and the use of face masks - we’ve got it all for you here.

Where Did the Virus Come From?

The first cases of the disease COVID-19 were observed in December 2019, in the Chinese province of Wuhan. How exactly the first infections occurred is still unclear. The most common theory right now is that the virus originated from bats. It may have found its way to humans via other animals [1].

In January 2020, researchers identified the SARS-CoV-2 virus in laboratory tests. Soon afterward, the number of cases of infection rose rapidly in China, and the disease developed into a pandemic - a worldwide epidemic. In Europe, the first cases occurred in northern Italy and probably spread from there to Austria and Germany. According to reports, the Austrian vacation resort Ischgl was a hub for the virus, ski vacationers* inside are said to have spread it from there throughout Europe [1].

Did you know? The abbreviation SARS-CoV-2 is the scientific name for the virus that is responsible for the pandemic. SARS stands for "Severe Acute Respiratory Syndrome". The disease that is caused by the virus is called COVID-19 (Coronavirus Disease 2019).

How Does the Virus Infect People?

The common way people get COVID-19 is through droplet infection. The virus spreads in tiny droplets of saliva that we give off when we cough, sneeze, and speak.

It has recently become increasingly clear that aerosol transmission is probably the most significant form of transition since we release these small particles into the air whenever we speak.

How Does Droplet Infection Take Place?

The droplets containing the virus are relatively heavy. They sink to the ground after a short time and travel about three to six feet. That’s why a safety distance of at least six feet from other people is advised in order to prevent infection.

Time also plays a role: the longer people stay close together, the greater the risk of infection. Sound scary? Here’s an easy rule of thumb you can apply to your everyday life: Try to avoid staying near other people for more than six seconds [4], [5].

Can I Be Contagious Even if I Don’t Have Any Symptoms?

Many people are contagious before they show any signs of the disease. Experts say this is one of the most important reasons why COVID-19 has spread so rapidly around the world.

According to an extrapolation by Chinese researchers, 44 percent of people become infected by people who do not yet have symptoms. Other scientists say 48 or even 62 percent would be more accurate [2,3].

Can I Get Infected Via Surfaces?

It is also possible to be infected via surfaces such as door handles and other objects. In such cases, the virus first gets to the victim’s hands via the surfaces. If they then touch their faces, it can get into their mucous membranes and respiratory tracts.

This route of infection is possible, but rare compared to droplet infection [4,5].

Aerosols: Can I Get Infected Via Exhaled Air?

The evidence that the virus can spread via the air we exhale has increased recently. For example, there was a case in which almost all the members of a choir became infected during rehearsals, despite social distancing. There have been similar cases in several countries. Researchers investigating these cases suspect that aerosols were released into the air during singing, which transported the virus [6].

The aerosol particles that we release into the air when we breathe are smaller and lighter than the droplets we emit when we cough, sneeze, and speak, and can probably remain in the air for longer. In one study, the aerosols remained in the air for up to three hours in closed rooms. Outdoors, however, they are quickly carried away by the wind [1,7,8].

Some scientists now assume that a large proportion of infections occur in this way. This is why they advise that we all regularly ventilate rooms and, if possible, hold meetings outside. In fact, this is probably even more important than washing your hands and disinfecting surfaces [9].

Am I Immune After I Recover From the Disease?

There has been a lot of debate about immunity to COVID-19 since the beginning of the pandemic. Immunity is what keeps you from getting sick, for example, when the flu is going around. Among other things, our immune system builds up certain antibodies that recognize and fight a pathogen. If the pathogen, such as a virus, then wants to get back into the body, the immune system already has identified it and can fend it off. We can then be said to be immune to certain viruses for a particular period of time.

There are indications that such immunity also exists with the SARS-CoV-2 virus. However, it is not yet clear how reliable, pronounced, and, above all, long-lasting immunity against the coronavirus will be.

How Long Could Antibodies Be Detected?

In a study published in October, Canadian researchers last detected a noticeably increased number of antibodies in patients’ blood four months after they had contracted the disease. Another recent American study examined almost 6,000 COVID-19 patients and still detected antibodies after five to seven months. The authors of both studies assume that immunity is maintained for at least that time period [37, 44].

Another US study from the end of October also found IgG (Immunoglobulin G) antibodies five months after infection - these are the antibodies that fight the coronavirus [45].

However, the question of immunity cannot conclusively be answered yet. It presumably also depends on how severe the case of COVID-19 was. If the case was very mild, fewer antibodies and other immune cells may be produced.

Did you know? Initial studies on monkeys and humans earlier this year suggested that it is probably very rare for people to be infected twice. As a rule, once you have survived COVID-19, you will probably be immune for at least a few months [1].

Are There Studies That Cast Doubt on Immunity?

In March, reports from South Korea and China stated that the coronavirus was found again in people who were already considered healthy. The study authors assumed that the virus could perhaps "reactivate" itself again.

Some experts suspect that these results are due to the common PCR (Polymerase Chain Reaction) measurements. The tests detect the viruses only in certain body parts and at certain times. They sometimes give a negative result in the throat, although the virus may be present in the lungs. This is not an indication that immunity does not develop after surviving COVID-19 disease [10,11].

What Are The COVID-19 Symptoms?

The symptoms of COVID-19 vary greatly from case to case. They range from "silent infections" without any symptoms to mild colds and severe cases of life-threatening pneumonia.

Symptoms in Mild and Moderate Cases

There are some studies from China, where the virus first broke out, on the symptoms. According to the studies, about 80 percent of the diseases were mild or moderate. Studies from other countries suggest that this proportion could be much higher [12].

Some people with mild cases of the disease had no symptoms at all, but often had symptoms such as a dry cough, fever, runny nose, and mild pneumonia.

Recent reports also show that the temporary loss of the sense of smell and taste could be a typical symptom. Around 15 percent of those affected noticed these limitations in their sense of smell and taste.

Other symptoms that have been observed include [1]:

  • Sore throat
  • Headaches and aching limbs
  • Loss of appetite and weight loss
  • Nausea, abdominal pain, vomiting, and diarrhea
  • Skin rashes
  • Conjunctivitis

Symptoms in Severe Cases

Severe cases of COVID-19 generally result in pneumonia. This is manifested by shortness of breath, and in very severe cases, lung failure which can spread to other organs.

These very severe cases can be fatal. Those affected must be treated in intensive care units in hospitals and often have to be put on respirators. Infections are fatal in 0.8 percent of cases. Researchers point out, however, that this figure is very difficult to determine - since the number of unreported cases of people infected is very difficult to establish [1].

How many of the corona infections lead to such severe cases has so far varied from region to region. The figures range from three to six percent of those infected [1,12].

Groups At High Risk for Severe Cases

To start with, we need to state that we are not talking about susceptibility here. All of us are equally susceptible to being infected.

The likelihood that individuals experience a severe case however will depend on various factors. This risk is significantly higher for certain groups of people. These include [1]:

  • People older than 50
  • Smokers
  • Obese people
  • People with certain pre-existing conditions such as cardiovascular disease, chronic lung diseases like COPD, chronic liver disease, diabetes, and cancer
  • People with a weakened immune system, for example, due to illness or the regular intake of certain drugs such as cortisone

There also seem to be some external factors that make a severe case more likely. The British government's Office of National Statistics last suggested in August 2020 that air pollution in large cities could have a negative impact on COVID-19 infections [42].

Did you know? Your Blood group could influence the risk of severe COVID-19 progression. In a recent study, people with blood group A positive had an increased risk profile and people with blood group 0 had a lower risk. However, your blood group is only one of many factors, so don’t consider your blood group either as a license for excessive worry or recklessness [13].

What Are The Long-Term Effects of COVID-19?

Some people who have been infected by the coronavirus may struggle with the effects for an extended period of time. Severe cases of COVID-19 appear to cause long-term damage to the lungs. Some patients report being short of breath for weeks after their illness and tend to feel out of breath even after minor physical exertion [15].

It is still unclear whether mild cases can lead to long term effects. However, neurological consequences such as a persistent decline in the sense of smell and taste are possibilities [1].

COVID-19 may also have an effect on other organs: Researchers have discovered effects on blood vessels and the heart. In a study in New York, nearly one-third of those treated in hospitals had kidney damage, requiring them to be put on dialysis machines [15,16].

Generally speaking, the exact long-term consequences still need to be researched. It is not yet clear how widespread, permanent, and severe the effects might be. But it looks like some patients will continue to struggle with the consequences of the infection for some time after having COVID-19.

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