Moderna vaccine results are stunningly impressive, Fauci says

The US' top infectious disease scientist Dr. Anthony Fauci on Monday hailed early trial results from Moderna's Covid-19 vaccine as "stunningly impressive," and said the findings were an emphatic validation of experimental mRNA technology that some had doubted. "The idea that we have a 94.5% effective vaccine is stunningly impressive. It is really a spectacular result that I don't think anybody had anticipated would be this good," he told AFP.

Fauci leads the National Institutes of Allergies and Infectious Diseases (NIAID), which began co-developing the vaccine with the US biotech company Moderna in January, shortly after China shared the genetic sequence of the new coronavirus. It is based on a relatively new technology that uses a synthetic version of a molecule called "messenger RNA" to hack into human cells, and effectively turn them into vaccine-making factories. No vaccine based on this platform has ever been approved. "There were many people who had reservations about using something that had not been tried and true over the years; in fact, some people even criticized us for that," Fauci said.

On Monday, Moderna and NIAID announced their preliminary results based on 95 of the 30,000 volunteers they had recruited who fell ill with Covid-19.

Fauci recalled that some had questioned whether the vaccine would prevent severe forms of Covid-19, not just mild or moderate cases and this too had been resoundingly answered.

A week ago American pharmaceutical firm Pfizer and its German partner BioNTech reported an efficacy of 90% for their vaccine.

Asked whether it was too early to say if mRNA technology had now been proven, Fauciq who is usually known for his cautious statements, said the jury was definitely in. "I think when you have two vaccines like this, that have proven to be greater than 90% effective, I think that mRNA is here, it's established itself, it doesn't need to prove anything anymore.

Traditional virus vaccines use actual viruses that have to be grown in chicken eggs or fetal cell lines and are weakened so they don't harm people, a process that can take many months. By contrast, the Covid-19 mRNA vaccines deliver the genetic information needed to create a protein that lies on the surface of the virus, called the spike protein, directly to cells in the human body, which then grow it. This primes the immune system to make antibodies to the actual virus, and has the major advantage of shortening vaccine development time to a matter of weeks, once scientists have the genetic sequence of the protein they want to create.

But there are still some unanswered questions, including how long the immunity lasts. Fauci said he was "certain" it would endure to some extent, as immune system cells called "memory B cells" remained on standby to generate new antibodies to the virus. But for how long was unclear. "We don't know whether it's going to be a year, two years, three years, five years, we don't know," he said.

The vaccine could receive emergency approval in the US within a matter of weeks.

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