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What are the differences between the vaccines? Which one is the right one for me? How quickly can people get vaccinated? Are there potential side effects? Here are some answers to the most important questions.
Three coronavirus vaccines are currently at the forefront of the vaccine race and have been licensed in the UK, the EU and the US: BioNTech-Pfizer's and Moderna's mRNA vaccines, and a vector virus vaccine co-developed by researchers at Oxford University and AstraZeneca. In addition, a vaccine has also been licensed in Russia, called Sputnik V, which is also a vector virus vaccine, and another in China.
Other manufacturers are also close to approval.
The vaccines licensed by European and US regulatory agencies are generally considered safe. It is not possible to say that one of the vaccines is better for certain target groups or age groups than others.
The vaccines from BioNTech-Pfizer and Moderna are so-called mRNA vaccines. They replicate individual proteins in human cells that are typical for the virus, and the body reacts to this by building up an immune defense. The most important difference between the two vaccines: Moderna's vaccine can be stored for up to 30 days in a normal household refrigerator.
It does not need to be refrigerated to -70 degrees Celsius (-94 Fahrenheit) during transport, like the vaccine from BioNTech-Pfizer. However, the latter can also be stored in the refrigerator for up to five days, just before using it.
AstraZeneca's vaccine is not an mRNA vaccine, but a so-called vector virus vaccine. It uses a harmless cold virus that normally infects chimpanzees as a transport mechanism. Thus, the vaccine transports the surface protein of SARS-CoV-2 to human cells, where it triggers an immune response against the coronavirus. A normal household refrigerator is also sufficient for this vaccine.
This is the only way to ensure that, for example, the frozen BioNTech-Pfizer vaccine is prepared professionally and then vaccinated promptly. The specialists warm up five vaccine doses at a time.
The complicated logistics are also why general physicians are not supposed to administer this vaccine to seniors living alone during home visits — at least in the beginning of the campaign.
The vaccination center system will also help reach those people who are most in need of vaccination first.
The BioNTech-Pfizer vaccine comprises two vaccination shots that need to be given three weeks apart — between 17 and 21 days. It's still feasible to give the second vaccination after this period, but it should be given as early as possible, according to guidelines from the US Food and Drug Administration.
The British health authorities have adopted a different procedure. The second vaccination is now administered there with a time delay of up to 12 weeks in order to be able to vaccinate as many people as possible at an early stage. Some German virologists have also advocated this procedure. However, the German Standing Commission on Vaccination (STIKO), has determined that in Germany the time window provided by the manufacturer and the licensing authorities should be adhered to.
No — the first and second vaccination must be those vaccines that have been recommended by the respective manufacturers and licensing authorities. At the moment, regulators don't have enough experience or test results with the various vaccines, so people shouldn't take the risk.
Anyone who has survived an infection with the virus can still get vaccinated and should do so. This is because it's not certain that surviving an infection provides adequate protection against reinfection, of which there have been recorded cases.
However, physicians should not vaccinate anyone who is going through a COVID-19 illness, a flu or a common cold. In that case, the vaccination should not be given until the patient has recovered.
The same applies to people who are in quarantine, because they have had contact with someone infected with coronavirus. They should not be vaccinated until the quarantine period is over. If they have already been infected, the vaccination would come too late anyway.
It will take years for everyone in the world to receive a coronavirus vaccine. Even in the highly developed industrialized countries, it will take at least until 2022 for everyone to get their turn.
Take Germany as an example: health authorities expect that 13 million BioNTech-Pfizer vaccine doses could be administered in the first quarter of 2021. At two vaccinations per person, that's not even enough for one-tenth of the population.
BioNTech CEO Ugur Sahin told DW that his company and Pfizer hope to be able to produce 1.3 billion doses next year.
Even if more vaccines come to market, it won't be enough for the entire world population of 7.8 billion. But it might be possible to protect those most at risk — seniors and patients with preexisting conditions — by next summer.
In principle, a doctor must first clarify whether certain preexisting conditions exist that preclude vaccination. This may be the case in particular with allergy sufferers who are allergic to certain ingredients, or have already suffered an anaphylactic shock.
But most allergy sufferers — for example, people who suffer from hay fever, animal or food allergies — will be able to get vaccinated. Other severe preexisting conditions, such as diabetes, obesity or even a weakened immune system, would be a reason to get vaccinated because these preconditions increase the risk of a severe course of COVID-19.
The current coronavirus vaccines are approved only for adolescents 16 years and older, and adults. Germany's federal health body, the Robert Koch Institute, says that studies on COVID-19 vaccination in children have been planned and, in some cases, are already underway. Currently, however, there is no vaccination recommendation for children.
Experts believe it's unlikely that the mRNA vaccines pose a risk to pregnant women and unborn children, yet animal studies on reproductive toxicity are still ongoing. For the moment, it remains a choice that should be discussed with a physician: on the one hand, pregnancy is considered a risk factor for severe COVID-19 courses, which can also cause severe harm to the child. On the other hand, expectant mothers should also assess the individual risk of infection — how much do they socialize, and how likely are they to be infected by COVID-19?
The STIKO currently does not generally recommend vaccination against COVID-19 for pregnant women, but does not rule it out either. Pregnant women with preexisting conditions and a high risk of COVID-19 can be offered vaccination after a thorough risk-benefit assessment and after doctors give their patients sufficient information, says the STIKO.
After vaccination, most vaccinated individuals experience mild to moderate side effects. These may include temporary swelling at the injection site, headache and aching limbs, chills, fatigue and also fever. The side effects usually occur in the first three days after vaccination and subside after about two days.
In cases of more severe complications the vaccinated person must contact the center or doctor who administered the vaccine, who will then report the case to regulatory authorities.
It's likely that both vaccines are also effective against the recently emerged mutant virus variant. BioNTech's Sahin said his company has already tested its vaccine on 20 virus mutations in a laboratory setting, including the latest variant that has appeared in southern England.
Other vaccinations, such as against influenza or mumps, measles and rubella, or against tetanus should be given 14 days apart before or after a coronavirus vaccination. This interval is currently considered a purely precautionary measure.
Although physicians assume that simultaneous vaccinations do not pose a problem, no data is available yet showing that simultaneous vaccination with other vaccines is harmless. So it's better to be safe than sorry.
That, of course, will ultimately have to be answered by religious scholars. But the chances are good: spokespeople for the three major manufacturers, Pfizer, Moderna and AstraZeneca , have confirmed to the Times of India that their vaccines do not contain any pig products.
While both vaccines provide up to 95% protection against coronavirus after two doses, even vaccinated people should continue to follow general hygiene rules, maintain physical distancing and continue to wear face masks.
There are still no studies on how long the vaccination protection lasts, and whether the vaccine can effectively contain the spread of the virus in the general population.
This article has been updated on January 13, 2021