Several vaccine candidates have moved, at breakneck speeds, into phase three trials. It is the last step needed before pharmaceutical companies can start applying for emergency use authorization from the FDA, and begin cranking out vaccines for yet to be determined groups of the population. 

What You Need To Know

  • Several vaccine candidates have moved into phase three trials

  • Phase three is the last step before pharmaceutical companies can start applying for emergency use authorization

Study participants received their first shots as part of the SARS-CoV-2 Phase 3 vaccine trial run by the NIAID, Dr. Anthony Fauci’s arm of the NIH, and the biotech company Moderna. Another front-runner in the vaccine race, Pfizer and BioNTech, announced their joint phase two-three trials have also begun.

The news signals there may very well be a vaccine ready for distribution by the end of the year, meaning the projected timeline of health officials like Fauci are on track.

In a press release, NIH Director Francis Collins said, “having a safe and effective vaccine distributed by the end of 2020 is a stretch goal, but it’s the right goal for the American people. The launch of this Phase 3 trial in record time while maintaining the most stringent safety measures demonstrates American ingenuity at its best and what can be done when stakeholders come together with unassailable objectivity toward a common goal.”

Both vaccine candidates are trying to enroll a combined 60,000 participants. The NIAID-Moderna vaccine will be tested at about 90 research sites around the country.

The Pfizer BioNTech Phase 1/2 clinical trials tested the safety and efficacy of four different vaccine candidates, narrowing it down to their most tolerable and effective candidate and will be tested it out on a global stage. 120 clinical sites have been selected in Argentina, Brazil, Germany, and 39 states in the U.S. The companies say they plan to recruit participants in communities that are often underserved medically and as a result have experienced a disproportionate burden of COVID 19 illnesses.

Late stage phase 2/3 trials are also underway in the U.K., Brazil and South America for an AstraZeneca vaccine candidate being tested by Oxford University. The group has plans to establish sites in the U.S. as well.

All three of these candidates have found the most robust immune response in participants that were given two doses, about a month or so apart. Reports of side effects are similar as well, and include pain and tenderness at the injection site, headaches, fatigue, chills, fever, and some muscle aches.

Mount Sinai Microbiologist Dr. Florian Krammer has been studying the antibody response to mild to moderate SARS-CoV-2 infections in his lab. A recently published preprint shows that neutralizing antibodies produced by those infections remain active and high for three months. Antibodies he says, that actually protect against the coronavirus. Krammer says the findings suggest this coronavirus behaves similarly to other known human coronaviruses.

“There were [antibody] studies where people look into the individuals who were infected with SARS-CoV-1, the virus from 2003 and that was two to three years. And for the human coronaviruses that cause common, colds, you see also one to two, maybe three years. The immunity doesn't go away completely,” said Krammer.

He theorizes a coronavirus vaccine may require booster shots, and cautions that much more research will be needed as vaccine trials continue.

“It's not clear yet how well these vaccines are inducing long-lasting antibodies. So we'll have to look right. But there is nothing problematic about getting it booster those every few years. There is actually a number of vaccines where that is needed,” said Krammer. “What has been done now for many years already is that when you license a vaccines and it's on the market, you're very often required to do a Phase 4 study. So you would still monitor a relatively large amount, a large number of people, that got vaccinated to find out if there any long-term effects that you might not find in the smaller population that you evaluated the vaccine in phase three. And so this is certainly going to be done for these vaccines.”

Experts, including Krammer, say it’s good news for the world that there are multiple candidates currently in phase three trials.

“The more producers you have, the more doses you can produce at once. If you have just one company and the company can only make certain number of doses per week, then you're stuck with that. If there's more than one company, you might double that or tripled that. So I'm pretty confident that the beginning of 2021 there will be ... Relatively widely available vaccine.”

In the meantime, he suggests there should be a more public conversation on who will get the vaccine first when it’s ready to hit the market.

“How are we trying to protect people who are most vulnerable? Which is basically older people, because the problem is that older people sometimes don't make a good immune response to it seems. So is it smart to vaccinate them? Is it smarter to vaccinate young people and indirectly protect old people? So, who will get the first vaccine?," asked Krammer. “Typically the CDC makes those decisions and organizes this. But I haven't heard much about that yet.”