Christmas time: Corona, flu, cold: tips before the holidays

As always, we pick Grandma up for lunch on Christmas Day.

Christmas time: Corona, flu, cold: tips before the holidays

As always, we pick Grandma up for lunch on Christmas Day. We are alone with the children on Christmas Eve. Do we want to go to Christmas mass again? In any case, on the second holiday we go to the in-laws. Two years ago, Advent looked very different. And the year before that we sat all alone in the living room and tested ourselves for Corona every morning...

Something like this is currently being planned in millions of households in this country. Maybe everything is already well planned out. The family comes together to admire the presents under the Christmas tree and the Christmas goose. By New Year's Eve at the latest, we want to dive into our circle of friends, dance and drink, lie in each other's arms with the best wishes as the hand advances to twelve. But wasn't there something?

It's not just gifts and mulled wine that are in season. A look at the streets, trains and buses or even at the crowds of Christmas markets and department stores gives the impression that everything is as it used to be. Of course we want to forget the pandemic. However, general practitioners' practices can hardly defend themselves from those who are currently seeking help for an "ILI". In international terminology, all the symptomatically similar illnesses that are caused by a flu-like infection are called: ILI – “Influenza like illness”. The Robert Koch Institute in Berlin, which is also responsible for such infections, summarizes the situation in weekly reports during the autumn and winter seasons. And they show a value for acute respiratory diseases that is well above average: a good seven million have been affected nationwide. About a quarter have already contacted their own practice or rushed straight to reception - with or probably without a mask. That's why the risk of encountering swarms of pathogens is not only high in the waiting room - all of them looking for new victims.

However, the actual flu season, the time of influenza or "real flu", has not even started yet, as the current data shows. Rather, rhino cold viruses, of which there are dozens, and also Sars-CoV-2 - Corona - currently dominate the field. In addition, RSV, the “respiratory syncytial virus,” is also increasing significantly, a danger especially for small children. But influenza hardly plays a role yet. Last year, however, everything started very early in the post-pandemic phase. However, in normal times the actual flu season only begins around the turn of the year. This year it seems to be the same again. So right when everyone gets together and gets close over the holidays. Just because the influenza numbers will probably also rise does not mean that the other pathogens will immediately leave the field. You can also become infected with more than one virus. So if in doubt, stay at home? Would you rather celebrate alone or in a very small group, if you even feel like it? But if my nose is just stuffy and no longer runs like it did a few days before, am I really still contagious? Or can grandma be cuddled again?

If you want to be absolutely sure and protect your loved ones as much as possible, you ultimately only have one option: as much distance as possible, ideally with house walls in between. Because neither Corona nor the flu or one of the many rhino cold viruses can be dangerous via email, chat or a traditional holiday card - unless the postman or postwoman delivers the greetings personally and exhales. Anyone who still wants to go out to celebrate together - and that's probably the vast majority of people - now has relatively simple means, known from the pandemic, to check their own status fairly accurately: rapid tests from the supermarket, drugstore or pharmacy . Such antigen tests are not only available for Corona, but also in combination for the two basic influenza types A and B, as well as for RSV.

This covers important pathogens, but by no means all of them that are possible for “colds”, i.e. flu-like infections. Is it then enough to at least pay attention to symptoms in yourself? In fact, the rule of thumb applies to the viruses mentioned: The time in which I can infect others roughly corresponds to the duration of my own suffering. But unfortunately that is not the whole truth. Let's look at a few details and start with Corona, because this pathogen and we have become used to each other in recent years and some considerations also apply to other "holiday viruses".

In fact, we have adapted: The Sars-CoV-2 virus no longer causes such a large number of serious illnesses that it was difficult to cope with even in intensive care units at the beginning of the pandemic. One of the most important reasons is that we – the potential “hosts” – have acquired a solid basic immunity through vaccinations and recovering from infections. That creates security. However, the broad immunity in the population still does not protect against infections, but “only” against their worse consequences. So basically anyone can become infected. The rule known from the pandemic continues to apply: the likelihood of a severe course of Covid-19 increases as people get older and have previous illnesses. Being careful when meeting others is therefore not just a question of politeness: Grandma is in her mid-eighties and has asthma. Aunt Frida has been living with high sugar levels for years. Anyone who brings such pre-existing conditions with them to the party still risks severe symptoms if they become infected with the corona virus, despite possible vaccinations and perhaps recovery. This doesn't have to end fatally. But the often diverse complaints associated with the still little understood “Long Covid” are not just talk or imagination. That much is now clear. And it can also catch younger and healthy people and paralyze them for a long time. A corona infection is always associated with a risk.

One of the early findings for the then new virus was the time of infectivity: around a day before the first symptoms appeared - if the virus became noticeable at all. Even today, viruses can still be expelled by infected people who do not show any signs of illness. Body aches and headaches, as well as an increased temperature or even fever (over 38 degrees) can of course still follow during the incubation period of a few days. In any case, a quick test shortly before the joint celebrations is definitely not a bad idea. And if there are symptoms? Then you probably don't feel like celebrating anyway. But even if you are feeling comparatively well again, the risk of infection for others is not yet zero.

A recent study with almost a hundred patients, in whom not only the usual tests were carried out, but also the swabs were also meticulously examined virologically, showed that adults with mild cases still excreted viable virus ten to fourteen days after the onset of symptoms. The decisive measure of the risk of infection was not the virus protein that is normally checked in rapid tests, i.e. the “spike” for the pathogen to dock onto the host cells. More important was the detection of a protein that comes from the pathogen's genetic envelope and is called N ("nucleocapsid"). If someone tested positive for this protein, then they also expelled “viable” virus. Sars-CoV-2 could therefore be obtained in a “culture” from a nasal swab and spread to cells. During this time there is also a risk of infection for others. However, no one is infectious at the push of a button or in the end. The concentration of the excreted viruses initially increases rapidly, but then falls relatively quickly as the Covid-19 disease progresses. It is also at its highest shortly before the outbreak and in the first five days afterwards. This also corresponds to the current medical recommendations formulated by the Robert Koch Institute. As a rule of thumb, two weeks after the start of your own illness is a sensible - although not guaranteed safe - time to be able to mingle with others again without any worries after Covid-19.

The fact that one's own illness symptoms are a certain measure of infectivity also applies to influenza. About a week after the first symptoms, there is usually no longer a great risk of infection for others. However, the range can vary. This means that children or people with a weakened immune system can shed the virus for much longer. And influenza is already contagious before it torments a person with symptoms. However, once symptoms have arisen, under real conditions in a shared household, there are hardly any further infections after about three days because the virus concentration has already dropped significantly. At least these are the results of a study presented in 2015 by the World Health Organization in collaboration with the University of Hong Kong and the Pasteur Institute in Paris. At least in adults, age or possible treatment with the flu drug oseltamivir played no role in infectivity. The exact type of flu virus also didn't make much of a difference in how long someone can infect others. However, another characteristic can surprisingly lead to an adult excreting the virus for longer than usual: being very overweight. A US team observed this a few years ago during studies in Nicaragua. Those who had a BMI (body mass index) of more than 30 and were therefore obese excreted the virus over a period of around 40 percent longer than their slimmer counterparts. This finding only applied to type A influenza, not to type B. For your own risk assessments just before the holidays, it may still make sense to plan an additional day for the infection phase. So together that would be at least five or six days after the onset of influenza symptoms instead of the average three or four days.

With the recommendation of the Federal Center for Health Education you are definitely on the safe side: stay away from others for a week from the first flu symptoms. In people with a functioning immune system, the same time period applies to infections with the RSV virus - three to eight days. However, this virus can also be highly infective before the first symptoms of the disease appear. And as a rule of thumb, the same time frame also applies to the many different rhinoviruses. But there is one difference between them: these cold pathogens and also RSV not only spread primarily through droplets and aerosols, but also very well through a smear infection. So they might “stick” to door handles, to the handrail on a bus or train, or to the handle of a shopping cart.

But once again as a warning: With all of the viruses mentioned, there may be a high risk of infecting others before they become noticeable to you through a runny nose, cough or hoarseness. So if you want to meet particularly sensitive people with a clear risk of a serious course of the disease over the holidays, you should consider a rapid test with a short time in advance of the visit. And it's certainly not a good idea to rush out to get the last gifts or groceries on Christmas Eve or even the day before. With a little common sense, you can stay on the safe side and still not be isolated. Of course, washing your hands thoroughly and wearing a mask are not prohibited even after the pandemic has officially ended.