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First Biontech / Pfizer, then Moderna, now AstraZeneca: Successes with corona vaccines are fueling hopes that the pandemic will end. How are the preparations different, when can they be available, and how do they work? An overview.
What is the status at Biontech and Pfizer?
The Mainz-based company Biontech and the US group Pfizer were the first Western manufacturers to publish the results of a study that is important for approval. The Biontech / Pfizer Hope Bearer has a strange name: BNT162b2. After a final analysis, the vaccine showed 95 percent protection against Covid-19, the company said. According to the company, there were no serious side effects.
US companies have already applied for emergency approval from the FDA. The European Medicines Agency (EMA) started an accelerated approval process for the vaccine (continuous view procedure).
How far is Moderna?
The American biotech company has caught up with Biontech / Pfizer. In an interim analysis, vaccination with the preparation called mRNA-1273 showed 94.5 percent efficacy in protecting against Covid-19.
Moderna plans to apply for an emergency permit in the US in the coming weeks. The EMA has already started an expedited approval process. The United States government is supporting the project with almost a billion dollars. The company, founded in 2010, began the first corona vaccine study in the US in the spring. Moderna has not yet launched any products.
And now a third vaccine?
British pharmaceutical company AstraZeneca also published the results of the study on its AZD1222 vaccine candidate. According to data from the preliminary study, the agent developed jointly with the University of Oxford offers an average of around 70 percent protection against Covid-19, AstraZeneca announced. According to the researchers, the hope for possibly greater efficacy leads to a surprising partial result of clinical trials: According to preliminary data, the vaccine is apparently more effective if test subjects receive only half a dose of vaccine instead a full dose the first time, followed by a full dose at least one. One month after. In this case, the vaccine shows an effectiveness of 90 percent.
Discussions with the US FDA on approval will begin this week, and the developers are also in contact with authorities in Britain and Europe.
How do vaccines work?
Like that of Pfizer and Biontech, Moderna’s preparation is a so-called mRNA vaccine. MRNA stands for messenger ribonucleic acid, also known as messenger RNA. It contains genetic information about the pathogen, from which the body produces a viral protein. The goal of vaccination is to stimulate the body to produce antibodies against this protein to intercept viruses before they enter cells and multiply.
Bottom line: with conventional vaccines, the antigen itself is injected, with mRNA, on the other hand, genetic information is injected for the body to produce the antigen itself. In the case of subsequent contact with the new coronavirus, the immune system basically recognizes the antigen and can fight the virus in a targeted manner. No mRNA vaccine has yet been approved for humans.
Unlike the Biontech / Pfizer and Moderna preparations, the AstraZeneca vaccine is not an mRNA vaccine, but is based on a conventional manufacturing method. The so-called vector vaccine is based on monkey adenovirus. It contains genetic material for a surface protein with which the pathogen Sars-CoV-2 attaches to human cells. The agent works in two ways: it is supposed to promote the formation of specific antibodies and T cells; both are important for the immune system.
What are the advantages of the mRNA principle?
According to the Paul Ehrlich Institute (PEI) responsible for vaccines and the Robert Koch Institute (RKI), the simple structure of RNA is one of the clear advantages. Many millions of vaccine doses can be produced in a few weeks. But it also needs more cooling.
Please store in a cool place – a problem?
It usually takes some time from the production of a vaccine dose to the injection. Also because the vaccine sometimes has to be transported long distances to a vaccination center. The following applies: the colder a vaccine must be stored, the higher the logistical requirements.
And here Moderna and Astrazeneca could have an advantage. The Moderna preparation can be stored for a comparatively long time at normal refrigerator temperature. The average is supposed to be stable for 30 days at temperatures of 2-8 degrees, the company reported. Plus, it can be stored for up to six months at minus 20 degrees Celsius. The vaccine could be “stored and transported at temperatures generally found in existing pharmaceutical freezers and refrigerators,” Juan Andrés de Moderna said, according to the press release. The vaccine is stable for up to twelve hours at room temperature.
The British company AstraZeneca’s vaccine can also be stored and transported at refrigeration temperatures of two to eight degrees.
The Biontech / Pfizer candidate is different: according to the company, this agent must be transported frozen at about 70 degrees below zero to the vaccination site. According to the pharmaceutical company, small portable ultra-low temperature freezers can be purchased at vaccination centers, which could extend shelf life up to six months. As it is today, once the potential vaccine reaches the vaccination site, it cannot be stored for more than five days between two and eight degrees, according to Pfizer. Therefore, dealing with the Biontech / Pfizer vaccine is likely to be a logistical challenge, especially in countries with less developed infrastructure and high temperatures.
What is known about the possible side effects?
Little so far. According to information from Biontech and Pfizer, there have been no safety-relevant side effects so far. However, virologists note that the observation period is very short.
Biontech had been developing its BNT162b2 since mid-January. The phase 3 study, which is crucial for its approval, began in late July. So far, the vaccine candidate has been tested in nearly 44,000 people, either with the real drug or with a placebo. A second dose followed after about three weeks. According to the manufacturer, protection by vaccination is achieved one week after the second injection.
Preliminary analysis of Moderna’s study included a total of 30,000 participants. The vaccine was also given in two doses. According to the data, the agent also protected himself against severe courses of Covid-19. The test subjects had only mild to moderate side effects. According to experts, the observed side effects, such as pain in the limbs and fatigue, are not uncommon with adult vaccines.
It is not clear whether the vaccine is equally effective in different groups, especially risk groups such as the elderly.
AstraZeneca also announced that its AZD1222 vaccine candidate had no serious side effects. According to the company, the vaccine works in different ages, including the elderly. 20,000 volunteers in the UK and Brazil participated in the series of tests.
How soon can a vaccine be available after approval?
To receive the coveted product at an early stage, the EU and other countries are already signing supply contracts with pharmaceutical companies. The EU Commission has already completed contracts with five vaccine manufacturers. The EU has already secured up to 300 million doses of the corona vaccine from Biontech and Pfizer. But even if Biontech goes into production before approval: the company is far from being able to cover these large quantities required, at least initially.
Negotiations are still ongoing with Moderna: the delivery of up to 160 million doses of vaccine is at stake. A contract has not yet been concluded. Moderna has also promised 100 million doses of vaccines for the United States. The United States government had provided massive financial support for vaccine development. Moderna left open how many cans will be available at the beginning of the year. In general, however, it is clear “that initially there will be much less vaccine than necessary,” said Moderna board member Juan Andrés el “Spiegel.”
AstraZeneca aims to complete 200 million doses of its vaccine by the end of the year and 700 million doses worldwide by the end of the first quarter of 2021. Numerous governments have already secured millions of them in advance, and the European Commission has signed a purchase contract for up to 400 million cans.
