Sinovac

Name: CoronaVac

Who: A Chinese biopharmaceutical company, in collaboration with Brazilian research center Butantan.

What: CoronaVac is an inactivated vaccine that uses a non-infectious version of the coronavirus to provoke an immune response.

Status: On November 17, preliminary results from Sinovac’s early trials, published in The Lancet, reported that the vaccine was safe but produced only a moderate immune response, with lower levels of antibodies compared to those in patients who have recovered from COVID-19. CoronaVac entered phase three trials in July, with plans to recruit nearly 9,000 healthcare professionals in Brazil, in addition to phase three trials in Indonesia and Bangladesh. Preliminary results in macaque monkeys, published in Science, revealed that the vaccine produced antibodies that neutralized 10 strains of SARS-CoV-2.

Moderna Therapeutics

Name: mRNA-1273

Who: A Massachusetts-based biotech company, in collaboration with the National Institutes of Health.

What: This vaccine candidate also relies on injecting snippets of mRNA into human cells to trigger an immune response. This vaccine requires two doses, four weeks apart. (Here’s how mRNA vaccines work.)

Status: On November 16, Moderna announced that an interim analysis of its phase three study shows the vaccine is 94.5 percent effective in preventing COVID-19—including severe cases of the disease—without any significant safety concerns. Like Pfizer, Moderna has not presented underlying data on how the vaccine produced these effects. In a separate announcement, the company also said its vaccine can be safely stored on ice or in a normal refrigerator for 30 days. Moderna intends to apply for an emergency use authorization with the FDA in the coming weeks.

Moderna started the third phase of its clinical trials in July. Preliminary findings from its phase one trials showed that healthy subjects—including elderly patients—produced coronavirus antibodies and a reaction from T cells, another part of the human immune response. Phase three is testing the vaccine in 30,000 U.S. participants; Moderna expects to have 20 million doses ready to ship in the U.S. by the end of the year and says it remains on track to deliver at least 500 million doses per year beginning in 2021, thanks in part to the deal it has struck with Swiss manufacturer Lonza that will allow it to manufacture up to one billion doses a year. In September, however, Moderna’s chief executive Stéphane Bancel told the New York Times that it was unlikely the vaccine would be widely available in the first half of 2021.

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https://www.nationalgeographic.com/science/health-and-human-body/human-diseases/coronavirus-vaccine-tracker-how-they-work-latest-developments-cvd/

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Pfizer

Name: BNT162b2

Who: One of the world’s largest pharmaceutical companies, based in New York, in collaboration with German biotech company BioNTech.

What: This vaccine candidate relies on injecting snippets of a virus’s genetic material, in this case messenger RNA (mRNA), into human cells. It spurs the production of viral proteins that mimic the coronavirus, training the immune system to recognize its presence. Any successful vaccine based on this technology would be the first mRNA vaccine approved for human use. This vaccine requires two doses taken 21 days apart.

Status: On November 20, Pfizer and BioNTech said they were filing for emergency authorization from the FDA just two days after announcing the conclusion of their phase three trials. The companies stated that they’ve met their primary goals: The analysis found the candidate to be 95 percent effective in preventing mild and serious cases of COVID-19—and 94 percent effective in adults over 65 years old—with no serious safety concerns. The announcement updates figures from an interim analysis released a little more than a week ago, wherein the companies reported 90 percent efficacy. As yet, they have provided no underlying data to back the claim, and it’s still unclear if the vaccine produces a durable immune response. The companies also haven’t explained if the vaccine works by reducing disease symptoms or blocking the virus entirely. Pfizer has also launched a vaccine delivery pilot program with four U.S. states—Rhode Island, Texas, New Mexico, and Tennessee—to prepare for deployment of the vaccine.

In July, the companies launched a trial that combines phase two and three by enrolling a diverse population in areas with significant SARS-CoV-2 transmission. It has expanded the trial to include 44,000 people across multiple countries. Preliminary results of phase one/two data showed the vaccine produces antibodies and T-cell responses specific to the SARS-CoV-2 protein.

Pfizer expects to be able to produce up to 50 million vaccine doses in 2020 and 1.3 billion doses by the end of 2021. It has signed a nearly $2 billion contract with the U.S. government to provide 100 million doses for free, though the New York Times reports that only half its supply will go to the U.S. this year. Questions have also been raised over the vaccine’s storage, which requires ultra-cold freezers set at minus 70 degrees Celsius (minus 94 degrees Fahrenheit).