Observing the development of the Covid-19 epidemic, most experts believe that sooner or later the coronavirus will infect a significant, if not the majority, of the world’s population. In the end, the number of infected people could reach seven billion, according to various estimates. There is a version that the infection will take hold and become seasonal, like the common flu. And if infection is only a matter of time, it is necessary to think not so much of how to avoid it, but rather of how to prepare for it: one must know the enemy personally.
The Russian service of the BBC answers common questions about the coronavirus SARS-CoV-2 (that is its official name). A virus is a tiny fragment of genetic code wrapped in a protective protein shell. Its particles are so small that they cannot even be seen under an ordinary microscope: 100 million copies of the new coronavirus could easily fit on the tip of a needle. Tiny size is one of the reasons it is so difficult to protect against viruses. When an infected person coughs, tiny droplets spread, each of which can contain billions of virus particles. Once inside the cell, the virus tricks the cell into making its own copies instead of normal proteins, and the infection develops. Science knows tens of millions of viruses, and new, previously unknown species are being discovered all the time. At the same time, the vast majority of them are completely harmless to humans – only a few hundred viruses pose a threat, and our immune systems have evolved to successfully fight many of them.
But viruses also evolve – and sometimes, through mutation, an infection that was once found only in animals gains the ability to invade the human body. Such “new” viruses are particularly dangerous because our immune system has never encountered them and has not yet developed a protective mechanism. As a result, the virus begins to actively spread among humans, creating an epidemic. This is exactly what happened with HIV, SARS, MERS, and now the new coronavirus.
According to Peter Piot, director of the London School of Hygiene and Tropical Medicine, SARS-CoV-2 has several important differences. First, a person may be asymptomatic for a few days after infection, but can infect others. This is particularly unpleasant because it makes it difficult to isolate the virus. In the case of SARS, for example, it was the other way around: symptoms appeared immediately, but the danger the sick person posed to others took days.
Second, up to 80% of those infected experience only mild discomfort similar to a cold or flu, and nearly one in five (18%) experience no symptoms at all, yet they remain a source of infection without even knowing it. Third, in the early stages of the disease, the virus is actively replicating specifically in the throat, so coughing spreads billions of viral particles around the infected person. And coughing is the first thing a sick person does – all other symptoms manifest (or not) later. In its mild form, Covid-19 resembles the flu or any other acute respiratory viral infection (ARVI), which is why many infected individuals do not even suspect that they have become carriers of the new virus. The most common symptoms are cough, fever, and general malaise. Less commonly, patients complain of headache or muscle aches. Covid-19 has a unique symptom: many infected people temporarily lose their sense of smell, and sometimes their sense of taste. It appears that the coronavirus can affect the nervous system as well as the respiratory system. However, the details of this mechanism are not yet understood. Not all infected individuals experience a loss of smell, but this symptom may be the only one or may occur earlier than others – so it is a reason to be alert. For more details on symptoms and preventative measures, click here.
Short answer – don’t expect it. Even if it is possible to develop it in the shortest possible time, it is unlikely to be useful to you. Although the first clinical trials of the vaccine have begun (and several variants are being tested simultaneously in different countries), even in the best-case scenario, mass production of an effective vaccine will not begin before the end of 2021, by which time a significant portion of those at risk will likely have recovered from the virus.
Moreover, although most experts are optimistic, there is no guarantee that a vaccine can be developed at all. The search for an HIV vaccine, for example, has been going on for 35 years – and still has not been successful. During that time, however, several drugs have been developed to effectively prevent the disease. The two main factors that determine the danger of any disease are its infectivity (how quickly and easily it spreads) and its lethality (how often it results in the death of the patient).
Ability to infect. According to initial calculations by Chinese doctors, in Wuhan (a city in China considered the epicenter of the COVID-19 pandemic), each infected person was able to infect an average of 2.2 healthy people. For the epidemic to decline, this indicator should be below 1. However, it should be remembered that Wuhan was quickly placed under quarantine, so the actual infectivity should be higher. When the virus outbreak began in Italy, each sick person transmitted the infection to an average of 3-4 healthy people.
And although the new virus spreads as easily as the common seasonal flu, it is far more contagious. It remains viable in the air for up to three hours and on plastic and steel surfaces for up to three days.
Mortality rates Various studies estimate the fatality rate of the new coronavirus to be about 1.5% of all infected individuals. This is about 20 times higher than the normal seasonal flu, but still far below SARS (10%) and MERS (35%). The virus poses the greatest threat to elderly people with weakened immune systems and chronic diseases. In the age group over 70 years, the mortality rate of Covid-19 exceeds 5%, and after 80 years, on average, every tenth infected person dies from the virus.
The epidemic evolves differently in different countries and is influenced by many factors. In one place, the average age of the population and the cultural and hygienic norms accepted in the society play the most important role, in another place – the general condition of the health care system, in another place – the experience of previous epidemics, which helped the authorities to take the necessary measures in time, and so on. The highest number of deaths was recorded in Italy, where the Covid-19 epidemic was detected almost two months late. As a result, the number of patients in the country skyrocketed to tens of thousands within a few weeks, and the Italian healthcare system was unable to cope with the peak load. In addition, Italy has a large elderly population, and the disease progresses significantly more severely with age.
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No, that’s not true – although, on average, patients under 50 actually tolerate the infection better than older patients. However, this does not mean that the virus does not pose a threat to their health and even their lives. Among the victims of Covid-19 are children, teenagers and young adults – without any known additional diseases. In addition, even if the disease is very mild – with few or no symptoms – the infected person remains a carrier of the virus and is dangerous to others.
Does the BCG vaccine offer additional protection against the virus? Scientists do not yet know for sure, but such a theory exists, and many experts find it plausible. In any case, preliminary calculations show a strong correlation between the rate of spread of the epidemic in a given country (number of infections and deaths per capita) and the tuberculosis vaccination policy implemented there. Trials are underway in several countries to understand whether this association is due to the effect of the vaccine and whether BCG makes people less susceptible to the SARS-CoV-2 coronavirus.
Short answer – not yet. Infected people are treated symptomatically, which means they are treated for the symptoms of the disease, not the disease itself. At the same time, scientists are testing several existing antiviral drugs to understand their effectiveness against Covid-19. However, convincing results have so far only been achieved in the laboratory, with animal experiments proving less successful. However, doctors stress that this is no reason to panic. The majority of people (over 80%) do not need medical attention. They treat themselves at home with remedies for the common flu – and recover, as usual, in about a week or a little longer. A recent study published in the Lancet calculated that Covid-19 lasts an average of almost three and a half weeks, but only in relatively severe cases where patients have to be hospitalized.
However, only about one in five or six patients require hospitalization, mainly the elderly and/or those with pre-existing conditions. If the infection progresses to viral pneumonia and the patient develops respiratory distress, they are admitted to intensive care. These patients account for approximately 4% of all diagnosed cases. As numerous studies and models have shown, the most effective way to fight the virus is to quarantine yourself so as not to infect others. At the first suspicion of Covid-19 (the first symptom is cough, then temperature may rise) – self-isolate together with your family members and if possible do not leave the house until complete recovery.
Do not take certain medicines without a doctor’s prescription. This is especially true for antibiotics – they are ineffective against viruses. Wear a surgical mask during all face-to-face communication. From a prevention standpoint, it does not provide much benefit, but it effectively protects others from the sickest person by catching droplets of saliva.
The main thing is not to panic and be prepared for the fact that you will most likely get infected sooner or later, even if you take all the necessary precautions. However, you may already have had it – you may have gotten away with a mild cough without a fever, or you may not have noticed any symptoms of the “dreaded virus” at all.