COMMON COLD CAN SOON BE CURED

A runny nose and a sore throat. Today, after catching a cold, all you can do is drink a hot cup of tea, but researchers are testing several effective treatments, and in a few years, avaccine may be available against the condition.

The commuters stand close to each other in the bus, and the damp oozes from their wet coats. Here and there, people take a handkerchief out of their pockets and rub it against their runny noses. Suddenly, a violent sneeze resounds through the bus. More than 100,000 cold virus particles fly out of the mouth of the sneezing person at a speed of approx. 100 km/h. Some of the particles land on the posts, which the passengers hold on to, and here, they can infect anybody who comes into contact with them during the next two days.

Only few people make it through the winter without suffering from a cold, and many of us fall ill two-four times a year. Fortunately, it is not that dangerous to catch a cold, but unlike many more severe illnesses, a common cold cannot be prevented or cured. At present, if you are infected, you can only wait until the snot stops running out of your nose after a few days.

Now, however, researchers are testing a range of promising cold medicines, and if some of them live up to the expectations, we will, in a few years’ time, be able to take a pill when we feel the first itching in the back of the throat, or even see our doctor to be vaccinated against most of the virus strains.

200 VIRUSES MAKE US CATCH A COLD

The common cold costs society billions every year. An American study shows that, on average, an adult wastes ten working hours every year because of the condition. Only one fourth of the time lost is spent under the covers at home. Most of the time is wasted when the infected people come to work, yet are so snotty and weakened by coughing or sore throats that they are less productive than normally.

The common cold is the most widespread infectious disease in the world; the reason being, among other things, that the condition is not caused by one particular virus, but by numerous different viruses. If, for example, you have fallen ill once due to rhinovirus HRV-A67, you have produced antibodies against it and will be immune to a subsequent attack. Yet, although HRV-A67 can no longer make you ill, your body remains completely unprepared for an attack by coronavirus HCoV-229E or any other of the approx. 200 common cold viruses that the researchers have identified so far.

Common to the many cold viruses is that they infect the cells in the mucosa of the nose and throat and develop the typical symptoms such as a runny nose and coughing. But this is where the similarities end. Effective medication against a cold should therefore not target one virus very precisely; rather use a scatter-gun approach and target the entire gang of cold viruses. This is why there is not yet a vaccine against common cold. Vaccines target very specifically and must be tailored to one single virus. For influenza, doctors can pinpoint one virus strain, which will probably hit us in the coming winter,and develop a vaccine against it. However, to effectively protect us against cold, the doctors would, in principle, need to have over 200 vaccines.

Yet, researchers do see a light in the darkness, since 99 of the known cold viruses are closely related and belong to the group of rhinovirus. Together, they are the cause of some 40 % of all cases of common cold, and they are so similar that it may be possible to develop a common cure against all of them.

PROMISING VACCINE WORKS ON MICE

In 2017, Professor of Immunology Rudolf Valenta from the Medical University of Vienna, Austria, took out a patent on a new vaccine, which aims to hit as many of the 99 rhinoviruses as possible. So far, the vaccine has been tested on mice and rabbits and has been effective against at least five of the stubborn viruses. But much work remains to be done by the researcher to optimise the vaccine so that it can defeat all of them, and then it has to be tested on test subjects. Valenta hopes that, at best, the vaccine will be approved for humans in 6-8 years.

An effective vaccine will be the ultimate cure for a common cold, as it will make people immune and prevent the condition from taking hold at all. But some people are naturally almost immune to catching a cold, and now researchers are trying to uncover the secret behind their invulnerability.

In 2013, Professor Sheldon Cohen of the Carnegie Mellon University in Pittsburgh, USA, recruited 152 healthy test subjects who accepted to have rhinovirus injected directly into their noses. In nearly a third, the virus did not take hold, and when the researchers studied cells from them in a microscope, a clear pattern emerged, showing who were infected, and who were not.

Cohen focused on the chromosomes, which are the carriers of our genes, in the white blood cells of the immune system. More precisely, he studied the so-called telomeres, which are placed at the end of the chromosomes like a kind of cap, which can be compared to the hard bit at the end of a shoelace. The telomeres in the test subjects were not of the same length, and it turned out that people with the shortest telomeres were at greater risk of catching a cold. 77 % developed an infection, while only half of the persons with the longest telomeres did.

It also appeared that those with the shortest telomeres were twice as likely to develop actual cold symptoms compared those who had the longest ones. Thus, the study indicates that immune cells with short telomeres are less efficient when it comes to fighting cold virus.

NEW MEDICINE ATTACKS THE VIRUS

In addition to a vaccine, researchers are working on several promising drugs to target cold viruses – mainly rhinovirus – even before it has made its way into the cells of the mucosa and started an infection.

When the rhinovirus is to infect a cell, it uses a kind of injection needle to inject its genetic material into the cell, where it assumes control and starts a production of thousands of new virus particles. The injection needle is a protein called VP4, which is placed inside the virus particle behind an-other protein, VP1. The VP1 sits in groups of five and makes up part of the virus particle. shell. For the injection needle to emerge, the five VP1 proteins need to slide apart and form an opening. Yet, this may be prevented by a new experimental drug, WIN 52084.

Other researchers are developing new weapons, which do not attack the rhinovirus, until they have entered the cell and are about to multiply. The gemcitabine substance prevents the formation of new copies of its genome inside the cell, and in 2017, South Korean researchers showed that this is a promising strategy. The researchers infected mice with rhinovirus and then injected gemcitabine directly into their noses. Remarkably, the substance completely prevented the infection from taking hold, meaning that the rhinovirus could not be traced at all in the mouse after eight hours.

INFECTED SNEEZE ON DOOR HANDLES

When a person suffering from a cold sneezes, thousands of virus particles can hover in the air for hours and infect people who inhale them. In 80 % of the cases, however, the infection is transferred via virus particles that attach to e.g. door handles, light switches or banisters. When touching the virus-infected surfaces, we get virus on our hands, which will invariably come into contact with our mouths, noses or eyes, and from here, the virus can make its way in to the respiratory passages.

An American study has documented that the risk of infection can be considerably reduced if we wash our hands several times a day. In the study, school classes from five primary and secondary schools were divided into two groups. The pupils in the one group were asked to be extra careful about washing their hands, and this simple piece of advice halved their number of sick days.

So while the researchers are busy developing effective drugs against cold viruses, the best piece of advice is to spend some of the waiting time washing your hands thoroughly.

By Gorm Palmgren in "Science Illustrated", Australia, issue 56, December, 2017, excerpts pp. 72-76. Digitized, adapted and illustrated to be posted by Leopoldo Costa.