'Historic moment': Here's where COVID-19 vaccines stand in US, abroad

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ByKate Larsen KGO logo
Tuesday, December 15, 2020
Here's where COVID-19 vaccines stand in US, abroad
Herculean efforts by scientists and physicians around the world resulted in more than 50 experimental COVID vaccines currently in global clinical trials. The focus in the U.S. has been on Pfizer, Moderna, AstraZeneca, and Johnson and Johnson.

SAN FRANCISCO (KGO) -- Herculean efforts by scientists and physicians around the world have resulted more than 50 experimental COVID-19 vaccines currently in global clinical trials. The focus in the U.S. thus far has been on the big four: Pfizer, Moderna, AstraZeneca, and Johnson & Johnson.

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On December 8, images of people in the UK receiving Pfizer's vaccine - the first clinically authorized, fully tested COVID-19 vaccine - were broadcasted around the world to much celebration. Three days later, the Food and Drug Administration granted Pfizer emergency use authorization for its vaccine in the U.S.

On December 17, the FDA will consider Moderna's vaccine for emergency use. If granted, the first doses could be administered by Christmas.

"This is an historic moment in the history of public health. It's an historic moment in the history medicine," said UCSF epidemiologist Dr. George Rutherford. "It's an incredible feat of modern molecular biology."

Here's the latest on vaccines in the United States and around the world:


Hopes have been high for AstraZeneca's vaccine, which is less expensive and easier to store than Pfizer and Moderna's mRNA vaccines, which require special freezers. But several communication missteps surrounding safety and efficacy data have reportedly damaged relationships with U.S. federal regulators. Trials are ongoing in San Francisco and Oakland.

Johnson & Johnson

Johnson & Johnson's vaccine is also very promising. It's unique in that it's just one dose for adults. Like AstraZeneca, it's easy to store and inexpensive. Johnson & Johnson is wrapping up global phase 3 trials, including at Stanford and the VA in San Francisco.

Dr. Rutherford expects promising efficacy data from Johnson & Johnson early next year. "The good news about Johnson & Johnson is they've decreased the size of their trial from 60,000 people to 40,000 people. You don't do that unless you're expecting a large effect."

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Pfizer and Moderna

Pfizer and Moderna are both about 95% effective. AstraZeneca's efficacy varies depending on dosage, but overall data shows it's 70% effective.

UCSF infectious disease specialist, Dr. Peter Chin-Hong, points out the FDA's original COVID-19 vaccine approval bar was 50% effectiveness. "These are amazing vaccines. You not only passed the test, you got like an A+++."

For context, according to the CDC, the measles vaccine, and gold standard, is 97% effective after two doses.

Flu vaccine efficacy varies season to season, but on average over the past 10 years in the U.S., flu vaccines have been about 44% effective.

Herd Immunity

"Right now, 60% of Americans say they will get the vaccine, but we need it to be 70% and over."

It's thought that if 70% of the population gets vaccinated, the U.S. will achieve herd immunity.

"What we're trying to do overall is protect the vulnerable members of our community who probably wouldn't get an immune response or maybe couldn't get the vaccine for other reasons," said Dr. Chin-Hong. "Herd immunity doesn't only effect whether you get infected or not, but it may also help with the intensity or severity of the disease."


Pfizer, Moderna, and AstraZeneca all require two doses.

Pfizer is 52% effective after the first dose. You have to get the second booster to achieve near full protection.

Dr. Chin-Hong explained why it's critical Pfizer, Moderna, and AstraZeneca vaccine recipients follow-through with their second dose. "There are two reasons why everyone should get their second shot.... The first reason is that if you have low levels of protection, there is a theoretical risk of getting resistance in the entire population of COVID. The second reason, which is equally if not more important, is you may get a response after the first dose, but we don't know how long or durable that response is. The second dose is kind of like an insurance policy that you'll be protected for multiple years."

Clinical Trial Timeline

"It only took two months to develop a vaccine and get it into clinical trials. That's unheard of," said Dr. Susan Buchbinder, an epidemiologist with San Francisco's Department of Public Health. Until the pandemic, she spent her entire 32 year career working on HIV vaccines and prevention.

She's now on the CoVPN committee, and is the principal investigator for San Francisco's Phase 3 AstraZeneca trial, being run out of the Bridge HIV clinic.

"There aren't any shortcuts."

"The reason that it was so quick, is that the technology for making these vaccines was already available because it was being used to create vaccines against other infectious diseases," explained Dr. Buchbinder. "For instance, the Johnson & Johnson vaccine, that's using an adeno virus 26 is actually the same one that I'm leading a trial of an HIV vaccine using the exact same backbone."

Rather than completing one phase at time, COVID-19 vaccine trial phases overlapped, which compressed the timeline. And at financial risk, biotech companies and governments manufactured and bought vaccine product before knowing whether or not they worked. "So that if a vaccine is found to be effective, you can actually roll it out immediately. Normally, you wait until after you show that it's effective, then you apply to FDA for licensure and only then do you start manufacturing the vaccine... does cost a lot of money to make this stuff," said Dr. Buchbinder.

Global Vaccine Progress

Around the world, China has five vaccine candidates that have reached phase 3 trials and are expected to ship globally. Their Sinopharm vaccine is reportedly 86% effective.

Russia, which approved the first COVID-19 vaccine 'Sputnik V' in August, is now reportedly struggling to manufacture the two-shot vaccine.

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