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After Biontech, Moderna has now also announced good interim results on the effectiveness of a Covid-19 vaccine. But we still know little about the two candidates. Ten questions to answer.
It is not yet clear which vaccines will win the race.
A week after Biontech and Pfizer, Moderna also published good interim results from an efficacy study. According to this, 94% of infections should be prevented by the vaccine. In Biontech it was 90 percent. This is full of hope. Whether vaccines will prove truly viable, however, still depends on many unknowns. Here we have put together ten important questions that will also be important when comparing different candidates.
So far, the companies have presented only a small amount of data in the form of press releases. Both vaccines use mRNA from viruses. The virus’s so-called spike protein is produced from this in the cells of the body. This is how the immune system can prepare a defense.
Moderna vaccinated 30,000 subjects in the United States, half with a placebo and half with the vaccine. Data processing began two weeks after the administration of the second vaccine dose. So far, 95 people have been infected with the virus, 5 of them in the vaccine group and 90 in the placebo group. There were 11 severe disease deaths, none of them in the placebo group. The vaccine therefore appears to prevent infections and protect against serious diseases. However, the database is still very small. However, it is also good that no serious side effects have occurred.
According to the Biontech press release, 94 people of the nearly 40,000 vaccinated people were infected with Sars-CoV-2 in the week following the administration of the second dose (active ingredient or placebo). Most of the infected people had been treated with a placebo. This asymmetric distribution of Covid-19 cases that have occurred suggests that the BNT162b2 vaccine protects 9 out of 10 vaccinated people from infection. An independent commission also found no serious safety concerns with regard to side effects. The study will continue until 164 infections have occurred, at which point the data will be published in a specialized journal.
No data on age distribution have yet been published. But information would be essential, because one goal is to vaccinate those at risk first – the elderly and those with previous illnesses or weakened immune systems. Often it is these people who develop poor vaccination protection. In the Pfizer and Biontech efficacy study, two age groups were selected, one group between 18 and 55 and one between 56 and 85. Moderna also included people over 65 in the study. However, the two companies did not provide any information on the age of the infected. Since there were only 94 or 95 confirmed infections, very few in the vaccine group, an age-dependent outcome assessment is not meaningful.
This is also not yet clear. It is also possible only with great effort to check whether vaccinated people can infect others after a possible infection. It would be very helpful if vaccination could prevent serious diseases. But it would be even better if he nipped an infection in the bud so that those affected could no longer spread the virus (sterilizing effect). Only then can the vaccine, such as measles vaccination, help protect the herd and also indirectly protect those at risk. However, a sterilizing effect is much more difficult to achieve than a protective effect that only alleviates the course of the disease but does not break the chains of infection.
There is still no evidence of this either. In the Biontech / Pfizer efficacy study, researchers measured vaccine protection 7 days after the second vaccination dose and that of Moderna 14 days later. The effects are very likely to wear off over time. For months, there has been debate about how long immunity is after a Covid 19 disease. There have been some cases of secondary infections, but they seem extremely rare. However, they do involve studies that indicate that antibodies decline relatively rapidly after an infection. What this means is still not clear enough, especially since another study found no decrease.
Protection was achieved after two vaccinations. It is currently unknown whether the vaccination will need to be repeated after two injections. The most common vaccines against other diseases need to be refreshed at regular intervals of several years. Regulatory authorities only approve vaccines that do not cause medical problems. But the issue of refreshments will become acute soon in the next year, when it should become apparent that vaccine protection has already decreased in those who were first vaccinated.
As with all other vaccines, the same is true here: it is possible to make a statement about rare side effects or harms that occur late if a large number of people have been vaccinated and have been observed for a long period of time. In general, little experience has been gained with mRNA vaccines. There is no approved mRNA vaccine yet, but they are considered safe. Contrary to what is sometimes claimed, viral RNA administered in this way cannot integrate into the human genome. It is also rapidly broken down by the body’s own enzymes.
It’s hard to say. Some mutations have already occurred and various strains of the virus are circulating around the world. However, no variant is yet known that would reduce vaccination success. Furthermore, our immune system always produces different antibodies when vaccinated with an effective vaccine. These are directed against different areas of the viral proteins. Therefore, a vaccination also works against a slightly modified virus. We are also confident that Sars-CoV-2 is genetically much more stable than, for example, flu viruses and is currently changing rather slowly.
Overall, not much. Because the vaccines currently being tested each contain different components of Sars-CoV-2. It is to be expected, however, that those with viral mRNA such as the vaccine candidate from German company Curevac will also have some protective effect. The University of Oxford / Astra Zeneca vaccine, on the other hand, consists of Sars-CoV-2 DNA, packaged in a genetic ferry. Other vaccines currently being tested in clinical trials contain inactivated viruses or protein components from the surface of Sars-CoV-2. Each vaccine must demonstrate that its ingredients can trigger an immune response.
Maybe a country in Europe. A few days ago the EU Commission concluded a supply contract with Biontech / Pfizer. If the vaccine is approved, companies want to deliver up to 300 million doses, the European Commission will handle the distribution. Each country should receive doses of the vaccine proportionally based on its population. However, the Biontech vaccine could be approved first in the United States and then delivered there first. Because the US had already ordered 100 million doses in a first tranche in July, while Britain had contractually secured 30 million doses of the vaccine, even in July.
Switzerland has meanwhile agreed a binding reservation of 3 million cans with Biontech / Pfizer, the contract is imminent. With Moderna, the federal government had already signed a supply contract for 4.5 million cans, as well as with AstraZeneca (5.3 million cans). The EU lags behind Moderna. According to its information, the EU Commission is currently negotiating with the company for the delivery of up to 160 million doses of the vaccine.
Many countries are currently developing strategies for this. Scientists and ethics experts recommend vaccinating older people and those with previous illnesses first, in case the vaccine is approved for them. Then it would be the turn of doctors and nurses, especially in hospitals and homes. The third group should therefore consist of people with socially important functions, i.e. teachers, educators, employees of health authorities, police or firefighters.
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