More than 7,000 employees of the Medical Center – University of Freiburg have already received their first COVID-19 vaccination. The start of mass vaccinations against the coronavirus marks the beginning of the end of the pandemic. Hopes are high for the corona vaccinations, but so are the fears of many people. How safe are the vaccines? Do we have to be afraid of side effects? Of long-term risks? What about the new virus mutations?

Which types of vaccines have been approved for COVID-19 vaccination in the EU so far?

Researchers are currently working on more than 150 possible vaccine candidates. Four vaccines have already been approved in the EU: the two mRNA vaccines from BioNTech / Pfizer and Moderna, and the vector vaccines from AstraZeneca and Johnson & Johnson.

Are vaccines that are approved this quickly safe?

Various aspects have contributed to the rapid development of vaccines against SARS-CoV-2. On the one hand, findings from basic research over the past 15 years could be used for the specific development of vaccines against Covid-19.

Furthermore, the period for developing a new vaccine depends on the availability of study participants and the frequency with which a disease occurs. The high general infection rates meant that in the group of study participants, after just four months, a good comparison could be made between the group that received the vaccine and the group that received a placebo.

In addition, study phases were partially carried out parallel instead of one after the other, approving authorities were also informed of interim results, which in turn gave the control of the vaccine studies for Covid-19 top priority, and finally production of the vaccine was ramped up before approval. The interlocking of all these mechanisms ultimately enabled vaccines to be developed and made available in a very short period of time.

How do mRNA vaccines work?

mRNA vaccines contain gene segments of the SARS-CoV-2 virus in the form of messenger RNA. Starting from the mRNA, proteins are produced in body cells after inoculation, which generate an immune reaction. The mRNA of the RNA vaccines is broken down by the cells after a short time and has no influence on human DNA. After the degradation of the mRNA, no further production of the antigen takes place.

mRNA-based vaccines have the advantage that a large number of vaccine doses can be produced within a few weeks. The mRNA-based COVID-19 vaccines currently have to be transported and stored at low temperatures (-20 to -80 degrees Celcius).

How do vector vaccines work?

The COVID-19 vector vaccine candidates contain harmless, well-studied carrier viruses, whose genome contains a gene that contains the blueprint for the SARS-CoV-2 surface protein, the spike protein. The virus does not multiply in the human body and therefore cannot cause an infection.

The vector virus invades human cells, but does not invade the nucleus. In the cells, the genetic information on the gene is read out and translated into protein. The spike protein formed acts as an antigen and stimulates the body's immune system to produce antibodies against SARS-CoV-2. In addition, a T cell response can be triggered. Vector viruses are controlled and eliminated by the immune system.

Vector vaccines have already been approved (e.g. Ebola vaccines), and they can be produced relatively quickly. They can be transported and stored at temperatures of 2 to 8 degrees Celsius..

How effective are the vaccines currently approved in the EU?

According to the current state of knowledge, the available mRNA vaccines achieve a reduction in corona infections with symptoms by around 90 percent. For the vector vaccine approved to date, an effectiveness of an average of 70 percent is assumed on the basis of the studies carried out.

Do the previously approved vaccines also work against the known mutations?

We don't know for sure yet. It cannot be ruled out that the vaccine effect against the mutations has been discontinued. These problems affect all vaccines. We will most likely need a booster vaccination to act on the new variants in the future. The good news is that the vaccines can be modified very quickly for the new mutations. The updated vaccines would probably not have to go through a full study program for approval. A similar procedure is already being followed with the approval of seasonal influenza vaccines.

Which vaccine reactions have been observed?

As with any vaccination, vaccine reactions can also occur after the COVID-19 vaccination. Vaccination reactions usually occur shortly after vaccination and last a few days. The following reactions have so far been observed with the vaccines that have already been used: reddening at the injection site, tiredness, headache, increased temperature up to fever, in rare cases also chills. So far, local and systemic reactions have occurred more frequently with mRNA vaccines (BioNTech / Pfizer and Moderna) after the second vaccination dose, while with vector-based vaccines (AstraZeneca) the frequency of vaccination reactions is higher after the first vaccination dose than after the second dose.

What long-term effects can occur?

As far as we know today, there is nothing to suggest that the currently approved vaccines have any long-term effects. However, even with a new vaccine against SARS-CoV-2, it is possible that very rare side effects will only be recorded during the course of surveillance.

Are people who have already survived a SARS-CoV-2 infection currently vaccinated?

According to the Standing Vaccination Commission at the Robert Koch Institute (STIKO), it can be assumed that people who have recovered from a SARS-CoV-2 infection or COVID-19 will at least temporarily have some protection against an illness. Due to this assumed immunity after an infection, to avoid excessive side effects and in view of the existing vaccine deficiency, people who were previously sick with COVID-19 should be vaccinated about 6 months after recovery, according to the STIKO. However, according to the data available so far, there is no indication that the vaccination poses a risk after a SARS-CoV-2 infection that has already passed through unnoticed.

How long are you protected after a vaccination?

According to the data available so far, the protective effect is 95 per cent within the course of a few months.

Can you get vaccinated while taking certain medication?

Immunisation is the priority. That means that also people suffering from cancer or any immunological disorder should be vaccinated. You have to be careful with e.g. increased immunosuppression, e.g. rituximab, azathiorprin, etc. In individual cases it is better to check before vaccination. But even in these cases we advise for vaccination. Your doctor will help you to select an optimal time point for your vaccination.

Can you get sick after vaccination?

Basically you can get sick after a vaccination. There is no vaccine that can completely prevent disease. But this disease, if it occurs, is much milder. And that is the essential thing in this pandemic - that we prevent a severe course or death. Therefore this vaccination is absolutely valuable.

Does the vaccination work equally well for everyone?

With the previously approved mRNA vaccines, the effectiveness of the vaccination is far less dependent on the age of the person being vaccinated than with other vaccines. So far, a good antibody response has been recorded in vaccinated people, immunosuppressed people usually react a little less well.

Should children also be vaccinated?

The vaccines are currently only approved for people over the age of 16.

Should pregnant women get vaccinated?

Since there is currently insufficient data on the use of the current vaccines during pregnancy, STIKO does not currently recommend vaccination during pregnancy. No data are available on vaccination during breastfeeding. However, STIKO believes it is extremely unlikely that vaccination of the mother while breastfeeding poses a risk to the infant.

Can a woman get vaccinated if she wants to conceive?

As long as there is no pregnancy, we recommend vaccination as soon as possible in order to enable virus protection before the pregnancy occurs.

The above information relates to the vaccines approved in the EU: the two mRNA vaccines from BioNTech / Pfizer and Moderna, as well as the vector vaccine from AstraZeneca.

Sources:

• Robert Koch Institute (RKI)
• Medical Center – University of Freiburg
• Info letter from the German Society for Nursing Science