Scientists focused on three approaches to developing a vaccine, each with its advantages and disadvantages.
The Trump administration wants to have millions of doses available by the end of the year. Still, experts warn that the unprecedented speed may be achieved by circumventing security measures, and there is no guarantee that any of the candidate vaccines will prove useful.
“My concern is that we won’t know the answers to key questions about safety and effectiveness if we plan to get the vaccine so quickly,” says Paul Offit, Director of the vaccine education center at the children’s hospital of Philadelphia.
The eight candidate vaccines are divided into three categories.
The first category can be called the classic method: injection of a killed version of the virus to mobilize the patient’s immune system. Three independent groups of Chinese researchers are testing inactivated vaccines.
The second method uses one virus to fight another.
Whether it causes COVID-19, Ebola, or the common cold, the virus itself is just a shell containing instructions for creating new copies of the virus.
In this new vaccine development strategy, scientists remove instructions from a single virus and replace them with instructions to create only part of the coronavirus.
The introduction of a modified virus does not cause illness. The virus infects some of the patient’s cells, but instead of copies of the dangerous virus, these cells produce only that part of the coronavirus. The patient’s immune system reacts to the coronavirus protein and can deal with the intruder later.
This approach is used by two groups of scientists from China and the UK.
The third strategy excludes intermediary. Instead of delivering instructions via a virus, researchers inject the genetic code of the coronavirus element directly to the patient in the form of DNA or RNA.
Two groups are working on creating RNA vaccines, and another is trying to develop a DNA vaccine.
The new methods are faster and more flexible, says Kimberly Taylor, head of biohazard vaccine development at the National Institute of Allergy and infectious diseases.
“They are perfect for pandemic platforms because they are usually created on the principle of “turn on and work.” They can be produced very quickly and quickly delivered to clinics, ” she explains.
Each technology has its pros and cons.
“We will not put all our eggs in one basket,” says Walter Orenstein, Deputy Director of the Emory University Vaccine Center. “Different groups are looking at what will work and what may not.”