What is the practical meaning of the term 'recovered' from the corona virus

Answering four questions about how people survive the corona virus and what happens afterwards
Editor's note: As of the time the news was posted (12/4/2020 at 23:00), it is reported in Israel that 11,145 are infected, 103 have died, and 1,627 have recovered. The USA, on the other hand, continues to bleed close to 20,500 dead in the USA

By: Tom Dushinsky, Director of Epidemiological Education, IUPUI University, Indiana, USA.
[Translation by Dr. Nachmani Moshe]

The corona virus is indeed scary, but despite the constant reports about the cumulative number of patients and the tide in the number of deaths, the reality is that most people who contracted the corona disease survived it. As the number of patients increases, so does another number: those who survived.

In the middle of March, the number of patients in the US who had officially recovered from the disease was close to zero. Today, this number is close to tens of thousands and it is increasing daily. However, recovery from the corona disease is much more complex than simply feeling better. The recovery involves the fields of biology, epidemiology and even bureaucracy.

How does our body fight the corona virus?
As soon as the person is exposed to the corona virus, the body begins to produce proteins called antibodies whose role is to fight the infection. After these antibodies begin to successfully block the virus and prevent it from replicating in the body, the symptoms of the disease usually begin to disappear and the person begins to feel better. Eventually, if everything goes as expected, the immune system will completely destroy all the viruses present in the body. A person who became ill following the penetration of the virus into his body and survived this period without long-term health effects or damages is considered a patient who has recovered.

Our immune system locates and destroys the viruses that have entered the body, and also remembers the invaders for future cases [Image source: Keith Chambers/Science Photo Library via Getty Images]
A person infected with corona will feel sick for seven days, on average, from the moment the symptoms appear. Even after the symptoms disappear, a small amount of the virus will still be found in the patient's body, and those who recover should remain isolated for three more days to make sure that they have indeed recovered and are no longer contagious.

What about vaccination?

In general, once you have recovered from a viral infection, your body will have cells called 'lymphocytes' left in it. These cells 'remember' viruses they have encountered before and can quickly react with them in order to destroy them again. If you are exposed again to a virus that the body has already encountered before, the antibodies in the body will stop the activity of the virus even before symptoms appear. The person becomes immune. This is the principle behind many vaccines. Unfortunately, vaccination is not perfect. For many viruses, such as those responsible for mumps, vaccination may disappear over time, leaving the person vulnerable to the same virus in the future. This is why it is necessary to vaccinate again and again from time to time - what is known as a 'booster vaccine' (an additional vaccine dose given to the patient after a certain period of time after the initial vaccination. The additional dose re-exposes the patient's immune system to the storage antigen, with the aim of restoring the high level of immunity that was lost for a period The time that has passed since the initial vaccination (for example, for the tetanus vaccine it is a period of 10 years).

Since the coronavirus is a new strain, scientists do not yet know whether patients who have already recovered from the disease are immunized against future infection. Doctors do find antibodies in the body of people who have contracted and recovered from the disease, and this fact indicates that a process of natural immunization is indeed taking place. However, the question still remains for how long this vaccination is active. Other viruses from the corona family, such as Sars and Mars, do create an immune response that protects the person at least for a short time. It can be estimated that this is also true for the new strain (SARS-CoV-2), but no study has yet been conducted that produced definitive results.

Why were so few officially declared patients who recovered from the disease in the USA?

This is a very dangerous virus, and therefore the 'Centers for Disease Control and Prevention' (CDC) are very careful when they decide what is meant by the definition "cured from the corona virus". Medical and diagnostic criteria must be met before a person is officially declared to have recovered from the disease. Medically, a person must be free of high fever (without taking antipyretics) for three consecutive days. They must show improvement in their other symptoms, including reduced cough and shortness of breath. And all these conditions must be met for at least seven full days from the moment the symptoms began to appear. In addition to these requirements, the guidelines of the 'Centers for Disease Control and Prevention' state that the patient must produce two negative results for the tests for the presence of the virus when these two tests were done at least twenty-four hours apart from each other. Only then, when both the condition of the symptoms and the conditions of the tests meet the requirements, a person is officially considered to have recovered from the disease, according to the 'Centers for Disease Control and Prevention'.

The condition for a second test, the results of which are negative, is probably the reason why a low number of cases of official recoveries from the corona disease were determined in the USA until the end of March. At the beginning of the crisis there was a significant lack of test kits in the US. So while there were many people who had definitely recovered over the past few weeks, their numbers could not be officially verified. During the coming weeks, as the country (USA) enters the peak of the epidemic, the focus will still be on testing those who show symptoms, and not on those who have probably already recovered. More people are now being tested as states and private corporations have begun to manufacture and distribute test kits. As the number of test kits available increases, the more tests are performed to detect the disease, and the epidemic eventually subsides, the more test kits will be available for those people who appear to have recovered from the disease. Following the examination of people who have recovered from the disease, the appearance of any new infection will help researchers learn and evaluate what the period of active vaccination for this virus is.

Once the person has recovered from Corona, what can he do?

Knowing whether or not the person is vaccinated against the corona virus after recovery will determine what people, communities and society as a whole will be able to do next. If scientists can prove that patients who have recovered are vaccinated against the corona virus, then such a person could, theoretically, help the medical system by being able to replace those who are currently sick. Once communities pass the peak of the epidemic, the number of new infections will decrease, so the number of recoveries will increase. As these trends continue, the chance of infection will decrease. As soon as the chance of infection drops to a low enough level, the instructions for the isolation and social distancing of the people, at the community level, will start to be more lenient, and then the businesses will start to reopen. Based on the events in other countries, in the US it will take months until the chance of infection is low enough. However, before these things happen, the USA and all the countries of the world will have to pass the peak of the epidemic. Social distancing works well in reducing the spread of infectious diseases, and it does so in the case of the corona virus as well. Many people will need medical assistance in order to recover, and social distancing should slow the spread of the virus and give these patients the best chance of recovery.

For an article in The Conversation

More of the topic in Hayadan:

• Corona detection through self-monitoring of the sense of smell
• In Israel they manage to reduce the number of deaths from Corona compared to China and Italy, whose health systems were saturated
• Declining the corona virus in one country is not a solution - we need a coordinated global strategy