Originally published on July 20, 2020 in https://cityofhideaway.org/docs-corner/f/moderna-vaccine-trial-results-in-plain-english
140 vaccines for COVID-19 are now being developed all over the world, with more than 30 in early human trials, and three in large scale, late stage human trials. Moderna in the United States is the first to have its vaccine’s Phase 1 trial published on July 14. Vaccine development is usually very time consuming, often taking 5-10 years to come to market, but the US government’s “Operation Warp Speed” and the billions of dollars invested in it, have resulted in a human vaccine trial just months after the viral genome was first sequenced.
The Moderna COVID-19 vaccine: Phase I trial summary and more
45 healthy adults between 18 and 55 years old were enrolled in the study. So no children, elderly or high risk patients with underlying medical conditions in this round.
The 45 people were divided into three groups, they either received 25 mcg, 100 mcg or 250 mcg doses of the vaccine.
Each person received TWO shots of the same dose 28 days apart.
28 days after the second dose, 100% of participants had antibodies in their blood, the levels were higher than in those who had antibodies after a natural exposure to COVID-19.
The antibodies produced in the blood by the vaccine were neutralizing antibodies, which means they can bind to the virus in a manner that blocks infection.
Most side effects were mild, including fatigue, chills, headache, muscle aches and pain at the injection site. Side effects were more common after the second dose, especially with the highest dose of 250 mcg.
Participants will be followed for one year after the second shot with periodic blood collections.
All the above is good news for a Phase 1 trial, which is always small for safety reasons.
What we don’t know at this point:
- How will the most vulnerable people, i.e. the elderly and those with underlying medical problems, react to this vaccine? Will they produce the same level of antibody response that the young and healthy volunteers did or will it be weaker?
- How effective is the vaccine going to be in preventing infection, symptoms, hospitalizations and death? For example, the seasonal flu vaccine is effective 45 -70% of the time, depending on the year.
- Will it provide complete protection or just enough to keep you out of the hospital?
- If you do get infected despite the vaccine, will you be able to infect others?
- For how long will the antibodies provide protection? Will you need booster shots? And if so, how often? Will the initial dosing consist of a two shot series?
- How many of us will need to be vaccinated to get herd immunity? In other words, what is the minimum percentage of people that need to get vaccinated so they can protect others who can’t or won’t get the vaccine?
Hopefully the above questions will mostly be answered in Phases 2 and 3 of the study. However, some of the answers may not be available until well after the vaccine has been given to the masses.
Later Phases:
Moderna’s Phase 2 is already ongoing with 600 people evenly split between 18-55 year olds, and older than 55 years. Participants will get either a placebo, 50 mcg or 100 mcg doses at both vaccinations, again 28 days apart.
Phase 3 will be significantly larger, and will start enrolling volunteers on July 27 with a goal of 30,000 participants. Half will receive a placebo and the other half will receive 100 mcg doses of the vaccine.
If Phase 3 is successful at the 100 mcg dose, Moderna says it can produce 500 million doses in the first year.
The record time for a new vaccine thus far is 4 years. Less than 10% of drugs in trials are actually approved by the FDA. Let’s see how Moderna performs in the end.
The AstraZeneca/Oxford vaccine Phase 1 trial summary coming soon…
Sue Royappa, MD, MPH