The good news is that there will be a vaccine against the novel Sars-CoV-2 coronavirus. Vaccine researchers, manufacturers and regulatory authorities are very confident about this. The bad news: it will take time. According to general belief, one to a year and a half – even if more optimistic signals are coming from China and other countries. In any case, it is very unlikely that an effective and approved vaccine will still be available during the current pandemic.
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Vaccine development is by no means always easy. Vaccines against HIV, malaria or tuberculosis have been researched for decades. But so far, the results are sometimes promising, sometimes unsatisfactory. You are still not there.
The situation is different with Sars-CoV-2. There is a lead. Stephan Becker, a professor at the Philipps University in Marburg and a well-known vaccine researcher, says that one can follow up on the development of a vaccine against Mers. Mers is a corona virus that appeared a few years ago. And the first human test phase, clinical phase 1, has already been completed. Becker says that he sees “no major difficulties in developing protection against Sars-CoV-2 compared to Mers”.
Immune system recognizes the enemy
In principle, vaccines work as follows: a vaccine is presented with a so-called antigen. It is part of a pathogen or a weakened pathogen that does not itself cause any disease. The immune system recognizes these particles as an enemy and develops antibodies. If it goes well, long-lasting memory cells form that can still trigger the production of these antibodies even after years.
The body knows the threat and does not waste time in the event of a real infection. The killer cells recognize the intruders and eat them, dissolve them or stick their surfaces together, making them ineffective. The disease is literally nipped in the bud.
So much for the theory. However, developing particles that do not themselves cause undesirable side effects is often complicated. Live, but weakened, viruses are vaccinated against measles, mumps and rubella. Against diphtheria and whooping cough, only dead cell components are injected which are sufficient to trigger a so-called “immune response”.
The Sars CoV-2 researchers are pursuing two paths. At the development of the Mers vaccine, weakened pox viruses – so-called modified vaccinia ankara viruses (MVA) – were used, which incorporated part of the genetic information of the coronavirus. This corona genetic information is the blueprint for a specific protein molecule, the “spike protein”. With this surface protein, the coronaviruses penetrate the cells of the human respiratory tract. If they are recognized in time, the antibodies can paralyze them.
“We need neutralizing antibodies against this spike protein,” says Thomas Kamradt, President of the German Society for Immunology and Director of the Institute for Immunology at the University Hospital Jena.
The second way in modern vaccine research is the use of so-called RNA or DNA platforms, a type of artificial virus that is also said to lead to the production of antibodies against the spike protein.
Both so-called platform solutions have the attraction that vaccines against other diseases can also be produced in this way. Klaus Cichutek, President of the Paul Ehrlich Institute (PEI), which is responsible for monitoring vaccines and medicines, says that approval of such a platform vaccine can create a “precedent” that will facilitate testing and approval of future vaccines shortened. With a new vaccine, it is possible to exchange only part of the genetic information for another pathogen and thus introduce a new antigen.
Cichutek reports that research into a Sars CoV-2 vaccine is underway in 35 working groups, institutes and vaccine manufacturers worldwide. One of the companies is Curevac in Tübingen, the company of Dietmar Hopp. Curevac works with an RNA platform and has announced that it may be able to deliver a vaccine in the fall.
RKI dampens hopes
“If the course is positive, we could start clinical tests around early summer,” said the SAP founder and patron of the Bundesliga soccer team Hoffenheim to the Bild newspaper. Because the pressure is extremely high, approval by the authorities should go faster than in other cases. “So we would be able to deliver the vaccine in the fall,” said Hopp.
The Robert Koch Institute (RKI), on the other hand, is dampening hopes of an early vaccine against the coronavirus. “Personally, I consider it realistic that it will be in spring 2021,” said RKI President Lothar Wieler on Wednesday. Everything that is bureaucratically feasible must be done. Clinical test phases cannot be shortened. “We have to have a security profile. Vaccines can have side effects. “
Cichutek hopes that the current race of government and private laboratories around the world will result in multiple eligible vaccines. The result could be that there is “now a good, later a very good vaccine”. Vaccine is not the same as vaccine, immunity is not equal to immunity. Corona viruses naturally only trigger “fleeting immunity”, as Christian Drosten, the chief virologist at the Charité, reports.
This means that a patient who has survived Covid-19 is initially protected against re-infection with Sars-CoV-2. But this protection wears off after months or years. In this case, unlike measles, for example, human immunological memory is not permanent. This is a special property of the corona viruses.
Florian Krammer, vaccination scientist at the Icahn School of Medicine on Mount Sinai in New York, confirms this. It is therefore important to generate long-lived antibodies by vaccination. The immunologist Thomas Kamradt says that it would be even better to generate a “cellular immune response” – not only antibodies are formed, but also long-lived T-lymphocytes, which can still prevent infection in the throat even after many years.
Sars-CoV-2 will not go away
PEI President Cichutek, however, warns of excessive expectations or requirements. “We are also very welcome to get a vaccine that provides good protection for weeks or months.”
But what is the use of a vaccine that is too late for the current pandemic? In general, Sars-CoV-2 will not disappear, unlike its predecessor Sars-1. It will therefore be necessary to continue to protect particularly sensitive population groups from infection in the future – similar to the annual flu vaccination, which is recommended above all to people over 65 years of age.
Drosten also says the Sars-CoV-2 virus will stay. And there is even good news associated with it. The current epidemic will leave herd immunity in the population that is constantly renewed – even without vaccination. This means that – unlike now – the spread is slowed down because many do not even pass on the virus.
Further articles
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And: Sars-CoV-2 is so similar to other coronaviruses that immunity against it also protects against Sars relatives. “Mankind will certainly not get the next Sars virus from an unknown animal source in the near future,” says Drosten.
All developments in the Corona crisis in our news blog
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