The most dangerous thing can happen when such a virus “learns” to spread easily from person to person – an influenza pandemic can begin. Today, no one knows what the consequences of a hypothetical pandemic will be, but we already know what they can be.

If we talk about seasonal influenza, which comes to us every year, fortunately, most people cope with it without any consequences: the symptoms disappear after about two weeks. But there are several categories of people who should not get sick with influenza. These are children under five, people after 65, pregnant women and people with some chronic diseases. Fortunately, there is a possibility to be vaccinated, and this is what the WHO recommends to do, first of all, to all those who are at risk.

Unlike many vaccines, which are enough to do on a certain schedule several times in childhood, the influenza vaccine should be repeated every year, during autumn, before the beginning of the seasonal epidemic, in order to develop immunity in two weeks. It is also possible to do it later, but there is a chance to catch the virus before the antibodies are produced.

Fears

Influenza vaccines appeared more than half a century ago, and today are considered the most effective means of prevention. We need to make a few remarks specifically for the sceptics and opponents of vaccines (not only against influenza).

First, it is true that vaccines can be dangerous. For example, a vaccine can cause anaphylactic shock from which a person can die. But it happens very rarely – incomparably less often than people die of influenza. In addition, influenza vaccines are made in medical institutions, where there are special people and special equipment to help the person, if it does happen. Anaphylactic shock, by the way, can also occur due to peanuts. It is not necessarily that it will be in the outpatient clinic.

Secondly, even after vaccination, people may get the influenza. But, if it happens, it is usually in a milder form in comparison with those who have not been vaccinated. There are more potential fears about any vaccine, of course, but in the end, there is a doctor who promotes vaccination and explains what to be afraid of and what not to be afraid of.

Practical vaccination

In Ukraine, vaccination against influenza is not “mandatory”. This means that if your employer, for example, does not pay for it, you will have to buy it yourself. But a few hundred hryvnias is not such a large price to pay for not missing a week of your life, not to mention something worse.

Usually, a small part of the population is vaccinated against influenza. But now there is hope that due to a pandemic of coronavirus infections, people will be more attentive to their own health (by the way, one of the influenza complications is pneumonia, which can be very insidious). Vaccinations can be made by a family doctor (you have to pay only for the vaccine itself) or in a commercial clinic, where it will be more expensive, though more convenient.

There are different influenza vaccines. Some, for example, cannot be done to pregnant women, although they need to be vaccinated against influenza. But in practice, in Ukraine, the choice is easier to make. Last season, we were allowed to use two vaccines that are suitable for almost everyone: one protected against four strains of the virus, the other against three. But in the next season there will be other viruses and therefore other vaccines.

As it is not difficult to notice, one of the problems with the influenza vaccine is that the virus changes from season to season, which means that the vaccine has to be renewed. This means time, costs and risks that the vaccine will not be effective against the virus. This is why scientists are developing a universal vaccine today. It is supposed to work equally well from year to year, no matter how the virus changes. But no such vaccine has now been approved for clinical use.

There are medicinal products, but…

In pharmacies you can find various medicinal products that, according to their manufacturers or some doctors, are effective against influenza. But they are not always effective against influenza in terms of evidence-based medicine.

As for the position of the WHO, it recommends such medicinal products as oseltamivir and zanamivir to reduce the duration of the disease and reduce the probability of complications. Both are approved by the FDA for the treatment and prevention of influenza. At the same time, the FDA emphasizes that the main prevention method is vaccination, and these medicinal products can not replace it.

The year before last, the U.S. department also approved the use of baloxavir marboxyl, developed and already approved in Japan. It is effective because you need to take it only once. But, as with the previous two – no later than 48 hours after the appearance of symptoms.

According to WHO estimates, only in the twentieth century it killed 300 million people. Before that, for many centuries, it had caused deadly epidemics all over the world. It was against the smallpox virus that the world’s first vaccine was created. It is a story that biology teachers tell in school and do the right thing.

More than two hundred years ago, the English physician Edward Jenner suggested that if cowpox – a similar but far less dangerous disease – were to infect a person, it would prevent him/her from getting “human” smallpox. The assumption was, of course, not out of the blue – dairymaids, who were infected from cows, usually did not get smallpox.

Long before Jenner, people were trying to fight this disease with the help of variolation. In simple words, it is when a healthy person is infected with smallpox in such a way that he/she becomes mildly ill. The method was effective, but dangerous – some people, unfortunately, were dying.

Jenner tested his hypothesis experimentally in 1796. At first, he infected an eight-year-old boy with cowpox and he got sick – easily, as it should have been expected. And then he tried to infect him with smallpox, and the boy did not get sick! It is clear that such research does not fit into the modern concepts of research ethics, but this is a different story. Since the beginning of the XIX century vaccine against smallpox was successfully used in different countries.

But back in the late 60’s people were sick with smallpox in Africa and Asia. To fight it, various methods and, in particular, vaccination were used. The fight proved to be effective, and the last case was registered in Somalia in 1977. WHO was already ready to officially declare the complete eradication of smallpox.

But the next year, in 1978, Janet Parker fell ill with smallpox – 40-year-old photographer of the Department of Anatomy, Faculty of Medicine, University of Birmingham. It was a completely extraordinary, and also incomprehensible, event. In order to avoid an outbreak, doctors urgently vaccinated more than half a thousand people who theoretically could have been infected from the patient.

Despite the efforts of doctors, Janet Parker died and became the last victim of smallpox in history. At the university where she worked, there was indeed a laboratory where the smallpox virus was investigated. This is where she could have been infected, but it is still not clear how exactly it happened.

In May 1980, WHO officially declared victory over smallpox.

Today, humans have no way to catch smallpox, because animals do not get it. However, for research purposes, the virus remains in two laboratories in the world: the American CDC and the Russian “Vector”. In 2014, however, several smallpox virus tubes were discovered in a laboratory in Maryland, where they were not supposed to be. Of course, they were destroyed and it is to be hoped that no more samples of the virus were accidentally stored anywhere.

Since the disease is already a thing of the past, routine vaccination against the virus is long gone. But it cannot be ruled out that the smallpox virus can be used as a biological weapon by terrorists. That is why the USA, for example, has a stock of modern vaccines. On the same basis, the medicinal product tecovirimat for smallpox treatment, approved by the FDA the year before last, has been developed recently

There are no medicinal products against it, but there are vaccines. WHO calls their creation one of the main achievements of medicine of the twentieth century. Thanks to them, over the past three decades the number of cases was reduced by more than 99%. But in Afghanistan and Pakistan, the disease still exists.

There is enough prejudice around polio vaccines. In Nigeria, for example, as early as in the 21st century, the vaccination campaign was partially halted due to claims by some religious leaders that the vaccine was causing infertility and other problems. This resulted in an outbreak of poliomyelitis.

Vaccination opponents point out that poliomyelitis vaccines themselves can be a source of health problems. Strictly speaking, there is some truth to it. For example, according to WHO, a weakened live virus that is part of vaccines can lead to paralysis. But it happens very rarely – in one case for several millions. This risk is incomparably less than the problems from which the vaccine saves.

There are three types of poliovirus: types 1, 2 and 3. Since 1999, there have been no cases of infection with type 2 in the world, so in 2015 WHO announced its eradication. Last year it also announced the eradication of poliovirus type 3, which last occurred in 2012 in Nigeria. Today, the world has only a type 1 poliovirus.

The success is obvious, but it is too early to rejoice. The problem is that poliomyelitis knows no borders. Since it is spread very easily, and most cases go unnoticed, any child without immunity to this disease, wherever he/she lives, is at risk. Therefore, we must strive to eradicate the poliovirus completely. Fortunately, this mission seems to be possible.