Coronavirus risk groups: for whom COVID-19 is dangerous

SARS-CoV-2, also known as the coronavirus, has spread worldwide at breakneck speed. In Germany, new cases continue to be registered every day. Although the disease COVID-19, i.e. an infection with the virus, is mild or even symptom-free in many cases, there have now been countless deaths in Germany, too. For certain risk groups, an infection with the coronavirus is considered particularly dangerous. Read here why this is the case, who these risk groups are and how these people can best be protected.

Coronavirus: who are the risk groups?

It is impossible to say with certainty how high the mortality rate is from infection with the coronavirus, as the current figures vary significantly between the affected countries. The average mortality from COVID-19 is 2.16 per cent (as of December 7, 2021). In Germany, it currently averages 2.05 per cent. (Status: 07.12.2021) 1

This shows that members of specific risk groups are more at risk. Men are much more likely to be fatal than women. Coronavirus infection is also hazardous for:

• elderly people
• People with a weakened immune system or people taking immunosuppressive drugs
• People with pre-existing conditions such as diabetes, cancer or cardiovascular diseases
• People with chronic kidney, liver or lung disease
• smokers
• people who are overweight
• people who are sedentary
• Persons with psychiatric or neurological diseases
• People with blood group A+
• People with trisomy 21
• pregnant women

If several risk factors come together in a sick person, for example, a previous illness and overweight or advanced age, this can, in turn, also increase the risk of a severe course.

 

COVID-19: Men die more often than women

The statistics so far show that men are more likely to die from COVID-19 than women. According to various studies, the probability of men dying from an infection with the coronavirus is around twice as high as that of women worldwide.

In Germany, the differences are somewhat more minor: According to data from March 2021, around 3.1 per cent of men who fell ill died of COVID-19 on average, and 2.7 per cent of women.

Experts suspect that the reason for the increased mortality among men is that men smoke more often and consume more alcohol, as well as suffering more frequently from type 2 diabetes, obesity or high blood pressure. They are, therefore, more likely to have criteria that favour an unfavourable course of the disease. Women are also said to have a more robust immune system. In addition, men travel more than women on average, which can promote infection.

Researchers have also found that men have more of the so-called ACE2 proteins in their lungs and bronchi – these are the receptors to which the virus docks and through which it enters the cells. The more ACE2 receptors there are, the more opportunities the virus finds to enter the cells.

Hormonal hair loss as a risk factor?

But there is another possible explanation, as improbable as it may sound at first: A US study in 2020 found evidence that people – especially men – with bald heads often suffer from a severe course. 12 The researchers attributed this to the fact that androgens (male sex hormones), which promote so-called hereditary hair loss (androgenetic alopecia), also increase the ability of the coronavirus to attack cells.

If further studies confirm this association, androgen-suppressing drugs could play a role in the treatment of COVID-19. A study from Brazil with 588 participants found a positive influence of the androgen suppressant proxalutamide on the length of hospital stay and mortality. However, further studies are still pending here.

 

Women more at risk after menopause

A study from London provides evidence that women after menopause could be more likely to be affected by a severe course than women before menopause. 15 According to this, the women surveyed showed more severe symptoms beyond menopause and had to be treated in hospital more often.

The researchers suspect that the hormone level, more precisely the level of the female sex hormones estrogen and progesterone, which decreases with menopause, is also the cause here. Both hormones and a breakdown product of progesterone (the neurosteroid allopregnanolone) support the immune system, for example, by stimulating the production of antibodies. There is also evidence of the anti-inflammatory effect of progesterone.

This could, therefore, be another explanation as to why women (especially young women) experience fewer severe courses of COVID-19 than men. It also supports the thesis that hormone treatments could be necessary in the therapy of COVID-19. However, further research on this topic is still pending.

Older people are more at risk from coronavirus.

Middle-aged and older people are the most significant risk group. From 50 to 60, the risk of a severe course of the disease increases with age. While there were initially hardly any infections among children under the age of ten, the mortality rate for those over 80 years old in China was 14.8 per cent at the beginning of the pandemic (as of March 12, 2020). 3

A total of 98,127 deaths related to COVID-19 were recorded in Germany by mid-November 2021. Of these, over 20,000 were in the over-70s group, and over 43,000 of the deaths were in the over-80s age group.

The reason for this is probably the weakened immune system in older people – due to age or previous illnesses. Typical symptoms of COVID-19 disease, such as fever, are just a reaction of the immune system to the infection. However, if the immune system is weakened, such symptoms often appear weakened or not at all, so those affected often only seek medical treatment at a late stage.

Weakened immune system as a risk factor

People with a weakened immune system are generally more susceptible to infectious diseases than healthy people. For example, people with a disease that weakens the immune system are considered immunocompromised. 7

In certain autoimmune diseases such as multiple sclerosis (MS), inflammatory rheumatism or chronic inflammatory bowel diseases such as Crohn’s disease, those affected sometimes have to take medication that suppresses the immune system – so-called immunosuppressants. Such drugs are also accepted by people after an organ transplant, for example, to prevent rejection of the foreign tissue. Drugs that inhibit the immune system include cortisone, for instance. According to the Robert Koch Institute, people who regularly take cortisone are still in the risk group for severe disease progression – even if the glucocorticoid dexamethasone is now used to treat corona patients who need artificial ventilation.

There are no corresponding studies or indications about thyroid gland diseases, even if they are autoimmune diseases. However, cortisone may also be necessary to treat thyroid disorders. This, in turn, can increase the risk of a severe course of the disease.

 

Pre-existing conditions and coronavirus: risk groups

Kidney or liver diseases and other serious illnesses, such as cancer, can severely impair the immune system, which is why coronavirus infection could be more severe in affected people, regardless of age.

Likewise, diabetes mellitus also leads to a weakened immune system in those affected by a health-prone body. A severe course of an infection with the coronavirus is therefore considered more likely in people with diabetes.

Cardiovascular diseases also increase the risk of a severe course of the disease in the case of a COVID-19 infection. These include, for example, coronary heart disease, heart valve defects or high blood pressure.

If a disease damages organs, this can also increase the risk of a severe course of COVID-19 – this is usually not the case if organs are affected by a functional disorder in the body but are not affected by it, as is the case for example, with the harmless metabolic disorder Morbus Meulengracht.

coagulation disorders and pre-existing conditions

According to studies, COVID-19 promotes the development of coagulation disorders, thus increasing the risk of thrombosis or pulmonary embolism. The risk of a severe course is, therefore, exceptionally high for people who already have a significantly increased risk of suffering a thrombosis, a stroke, a heart attack or a pulmonary embolism. In such cases, anticoagulants are often administered as soon as COVID-19 is suspected. 

This applies, for example, to people with diabetes, high blood pressure and other vascular diseases.

According to experts, the risk of a severe course is not increased in people whose essential risk is slightly increased due to other preconditions, such as taking the pill or suffering from factor V, so they do not become a risk group counted. However, since a more extended stay in the hospital can increase the risk of thrombosis, the treating doctor should be informed about such preconditions. 18

People taking anticoagulant medication should continue to take it but also ensure they get enough exercise and eat a healthy diet.

Lung diseases increase the risk.

The respiratory disease COVID-19 is hazardous for people with lung disease. Affected are, for example, people with COPD (chronic obstructive pulmonary disease), chronic bronchitis or severe asthma (also allergic asthma).

However, people with asthma cannot be assigned to a risk group across the board – here, it depends very much on the age and general state of health of the person concerned and whether the asthma is well controlled with medication.

Experts assume that people with well-controlled asthma are not at a higher risk than others. The asthma drugs could even make it more difficult for the virus to enter the body because they block the necessary ACE2 receptors. For this reason, those affected should continue therapy with cortisone for severe asthma unchanged.

 According to the European Center for Allergy Research Foundation (ECARF), people with hay fever do not have an increased risk because they are not considered to be immunocompromised. A study by Queen Mary University of London also provided initial indications that allergy sufferers might even have a lower risk of contracting COVID-19. One reason could be that, on average, people with allergies have fewer ACE-2 receptors. Hyposensitization should be continued for pollen allergy.

 

Are you smoking as a risk factor?

A study from Great Britain, which was published in 2021, has now provided clear evidence that smokers have twice the risk of suffering a severe course of the disease after being infected with the coronavirus than non-smokers. Overall, in their study, the researchers evaluated data from over 1,600 people who were proven to be infected with COVID-19.

The reason for the increased risk is both the damage to the lungs caused by smoking and the damage to the blood vessels (calcification of the arteries). Based on these results, it is advisable to stop smoking to protect against severe courses of COVID-19 infection.

Whether smoking could reduce the risk of contracting the coronavirus is still being investigated. Different scientists suspect nicotine has a specific protective effect since the substance may attach itself to the same receptors the virus also binds to. This could prevent the virus from sticking to the cells and entering the body. For example, ongoing studies are looking at whether nicotine patches could promote healing in people in intensive care units for COVID-19.

Canadian researchers suspect a similar connection in the medical use of cannabis. Cannabis strains high in the anti-inflammatory compound cannabinoid ( CBD ) and less intoxicating tetrahydrocannabinol (THC) are said to reduce the ability of the coronavirus to enter and lodge in the lungs.

The researchers draw their conclusions from studies on Crohn’s disease or arthritis. Similar to nicotine, however, there is currently no comprehensive scientific evidence to support this assumption. 10

Being overweight increases the risk of serious illnesses.

Various data analyses have shown that being overweight ( obesity ) also increases the risk of a severe course of COVID-19. The data suggest that people with a BMI over 30 are particularly at risk. 9,16 Severe courses, especially in younger sufferers, can often be traced back to this. In a British study, the risk of hospitalization increased from a BMI of 23 and the risk of death increased from a BMI of 28. 2

One possible explanation is that being overweight makes breathing more difficult because the diaphragm and lungs have less space to expand. At the same time, however, the increased body weight is accompanied by a higher demand for oxygen. In addition, there are often concomitant diseases such as high blood pressure, diabetes or cardiovascular problems and an increased risk of thrombosis.

Another assumption is that the excess fat in the area of ​​​​the internal organs could promote the immune system’s overreaction (release of inflammatory substances), which is possible with COVID-19. In addition, an unhealthy diet, which is often associated with obesity, could be responsible for deficiencies in essential vitamins and minerals.

Lack of exercise increases risk.

Lack of exercise is also one of the possible risk factors. A large observational study from the US concluded that lack of physical activity increases the risk of developing severe COVID-19 or dying from the disease. 20

Even if the study cannot prove the connection due to its study design, it indicates that regular exercise can help protect against a severe course of the disease.

In addition, physical activity is essential to positively influence other risk factors such as obesity, diabetes or cardiovascular diseases. The World Health Organization recommends getting at least 150 to 300 minutes of physical activity weekly.

 

Blood group as a risk factor?

Researchers from Norway and Germany have discovered that certain blood groups could influence the risk of severe courses. 11 In their investigations, the scientists compared genetic factors in people who were severely ill with COVID-19. They found evidence that blood group A with a positive Rhesus factor could increase the risk of a severe course. Blood group 0, on the other hand, seems to be particularly seldom seriously ill. Both blood groups (A+ and 0+) are equally common in Germany.

The possible connection had previously been shown by Chinese and US researchers. However, further research on the subject is still pending.

The Robert Koch Institute sees a connection between blood group A and the severity of the course as possible. The Institute does not provide any information on the importance of the Rhesus factor. Particular antibodies that bind to SARS-CoV-2 and differ depending on the blood group could prevent infection. On the other hand, blood group-specific antigens and differences in tissue could increase the risk of a severe course. According to the Robert Koch Institute, however, these distinguishing features are not robust and are subordinate to other risk factors for the course of the disease.

What is the risk for pregnant women?

Even if many diseases are particularly threatening for pregnant women and children, according to the first level of knowledge, COVID-19 does not seem to be one of them. 5,6 Early data from China suggested that women are no more vulnerable than other women during pregnancy. However, more recent findings have indicated that the risk of severe courses in pregnant women could be increased. 17,19 Infection with SARS-CoV-2 can promote preeclampsia, and premature births and stillbirths also occurred more frequently in an observational study. 21

An analysis of various studies on COVID-19 diseases during pregnancy published in September 2021 concluded that around ten per cent of the pregnant women diagnosed with COVID-19 who were examined as part of the studies had a severe course. Four per cent had to be treated in intensive care. A total of 41,664 cases worldwide were considered in the studies. The risk of pregnant women for a severe course was thus increased.

The study data are less meaningful about mortality since the corresponding studies only examined a relatively small number of test persons (approx. 4,800 women). However, despite the increased likelihood of a severe course, the results do not indicate an increased mortality in pregnant women.

To reduce the risks associated with a coronavirus infection during pregnancy as best as possible, pregnant women and their close contacts should protect themselves particularly thoroughly against infection with the coronavirus and, if possible, be vaccinated.

Transmission of the virus to the unborn child or via breast milk has so far only been observed in rare cases. However, transmission to newborn babies through droplet infection is possible.

Are children particularly at risk?

There is no evidence of an increased risk in children. On the contrary, Previous data shows that children can be infected with the coronavirus but usually show weaker or no symptoms. Somewhat more frequently, the disease also manifests itself through other symptoms, such as vomiting, diarrhoea or abdominal pain. A severe or even fatal course is extremely rare in children.

Whether the new virus variant Omicron could lead to a higher hospitalization rate for children has not yet been clarified.

 

MIS-C: Syndrome in children secondary to COVID-19

Isolated cases of an inflammatory syndrome similar to Kawasaki disease have been observed in children in different countries. They could be linked to COVID-19. 8 physicians speak of the pediatric inflammatory, multisystem syndrome or the “multisystem inflammatory syndrome in children” (MIS-C).

The symptoms include gastrointestinal complaints such as abdominal pain, nausea, diarrhoea or vomiting, fever, accelerated heartbeat, and skin rash. This hyperimmune response is usually easily treatable but is attributed to about 1,000 deaths worldwide.

A US study examined whether there was a connection with a coronavirus infection. The results indicate that MIS-C occurs rarely and only about a month after a coronavirus infection. Compared to Kawasaki syndrome, older children are more likely to be affected by MIS-C, and the inflammatory reactions are also more severe. 13:14

A combination of several risk factors

The Robert Koch Institute points out that several risk factors can further increase the risk of a severe disease course. 6 If different underlying diseases or older people have pre-existing conditions, a higher risk can be assumed than if a single risk factor is present.

You can use our self-test to determine whether you belong to one of the risk groups.

Why do people from non-risk groups also die from COVID-19?

Infection with the coronavirus is not only dangerous for members of risk groups. Although they are more likely to develop a severe course of the disease, a challenging course cannot be ruled out even in young, healthy people.

Since risk groups comprise a smaller population, most infected (in absolute case numbers) come from non-risk groups. Numerous deaths have, therefore, also been recorded among people who do not belong to any of the risk groups. The infection can also be fatal for young, healthy people. Why this is so has not yet been conclusively researched.

One possible explanation is that these people may have exceptionally high protein receptors in their lungs targeted by the virus. Another reason could be that these people were already suffering from an immune deficiency or previous illnesses that had not been recognized up to this point.

Other suspicions are that these people were exposed to an exceptionally high dose of the virus or that the virus went directly to their lungs instead of first multiplying in the throat, which would give the body time to produce appropriate antibodies.

Protect risk groups from the coronavirus.

But what can risk group members do to protect themselves from infection with SARS-CoV-2? The Robert Koch Institute recommends that these people be particularly careful and attach greater importance to the recommended hygiene measures. 4 The following tips can help you to protect yourself from infection with the coronavirus:

1. Keep your distance from other people, especially if they are showing symptoms of an illness. If possible, do not shake hands with other people.
2. Wash your hands thoroughly with soap regularly, especially after contact with other people or objects that could be contaminated with the coronavirus. Preventive disinfection is not required.
3. Try not to touch your face so that possible pathogens on your hands do not get to your mucous membranes and, thus, into your body.
4. If necessary, ask members of non-risk groups to do your shopping and errands for you so that you can avoid crowded places more easily. However, make sure to avoid direct contact as much as possible.
5. Cancel trips and appointments and try to stay home as much as possible. Always observe the current measures taken by government agencies in this regard.
6. Get vaccinated according to the Standing Committee on Vaccination (Stiko) recommendations, especially against diseases that could weaken the lungs. These include influenza, pneumococcus, and whooping cough.
7. Strengthen your immune system, for example, through a healthy, balanced diet and sufficient exercise.
8. Find out about possible signs of COVID-19 and take care of your body. When the disease symptoms appear, seek medical advice or contact other counselling centres (please telephone).
9. If cases of coronavirus infection are known in your private or professional environment, be sure to let them know to speed up the diagnosis.
10. Get vaccinated against the coronavirus. Vaccination offers the best possible protection against severe or fatal disease progression from COVID-19.

In addition, find out about current reports and note any new warnings. Here, you will find the latest news about the coronavirus.

Others can do this to protect risk groups.

It is also essential for people who deal with members of risk groups to strictly comply with the usual hygiene recommendations.

Avoid shaking hands, remember to wash your hands and observe sneezing and coughing etiquette. Wearing a face mask as a precaution can protect other people from the potentially contagious droplets you expel when you speak, sneeze or cough. This could prevent infected people without symptoms from spreading the virus unnoticed.

Offer members of risk groups the opportunity to do the shopping for them and protect themselves from infection with SARS-CoV-2 so as not to infect others.

However, the same applies here: Vaccination ensures the best possible protection for risk groups, as this is the only way to reduce the spread of the coronavirus.