Developing a new vaccine usually takes years, but companies and governments around the world are racing to create one to neutralize the pandemic coronavirus. There is some hope for a relatively quick turnaround today. US-based biotech firm Moderna says its initial human vaccine trials have been a success with all patients developing antibodies against the virus.
As with any vaccine, the goal with coronavirus is to get the immune system to produce antibodies that can eliminate the virus. That’s what happens naturally when someone becomes infected with the virus and survives, but a vaccine saves you from all the dangerous symptoms of infection. Moderna, like other vaccine researchers, has focused its efforts on the Spike protein coronavirus uses to enter cells. Antibodies keyed to the spike protein will attach to the Spike and prevent it from attaching to the receptors on your cells. Moderna tested three different vaccine dosages across 45 study participants, and all of them have developed neutralizing antibodies.
Moderna’s approach to developing this vaccine relies on viral RNA rather than the finished virus particle. All current vaccines used in humans use all or part of the target virus to train the immune system, but an RNA vaccine is potentially faster to develop. RNA is the step between DNA and proteins, so allowing immune cells to take up this foreign DNA causes them to produce the viral proteins and prompt an immune response.
Here, Moderna has isolated a segment of genetic material called mRNA-1273 from the SARS-CoV-2 virus that codes for the Spike protein. It administered 25, 100, or 250 micrograms of mRNA-1273 to patients, and all of them developed antibody levels similar to people who recovered from COVID-19 infection. The only side effects were minor redness and injection site pain among those who received the highest dose. The next phase will test doses between 25 and 100 micrograms.
This is the first COVID-19 vaccine to make it through the first round of clinical trials. On its accelerated timeline, Moderna hopes to begin testing larger groups of people in the coming weeks. The next phase of clinical trials will start with 600 people, expanding to as many as 1,000 in July. The company and public health officials will need to evaluate all the data before making the vaccine publicly available. Best case, the vaccine could be available later this year or in early 2021.
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