Pfizer vaccine 90% effective, 10 million doses earmarked for Australia

The Pfizer/BioNTech vaccine against Covid-19, which is among the four vaccine treatments secured by the Morrison government for free distribution in Australia, has been found to be protect most people from Covid-19, according to a study hailed by the top U.S. infectious-disease specialist as "extraordinary."

The shot prevented more than 90% of symptomatic infections in the trial of tens of thousands of volunteers, the most encouraging scientific advance so far in the battle against the coronavirus.

While the results are preliminary, they may pave the way for the companies to seek an emergency-use authorization if further research shows the vaccine is also safe.

The findings are based on an interim analysis conducted after 94 of the trial’s 43,538 participants, split between those who got a placebo and those who were vaccinated, contracted Covid-19.

The trial will continue until 164 cases have occurred. If the data hold up and a key safety readout Pfizer expects in about a week also looks good, it could mean that the world has a vital new tool to control a pandemic that has killed more than 1.2 million people worldwide.

With effectiveness for the first vaccines previously expected to be in the range of 60% to 70%, a rate of more than 90% “is just extraordinary,” said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, on a call with reporters.

Trials continue, with a promising outlook

The data does have limits: it isn’t known how well the shot works in key subgroups, such as the elderly.

And it isn’t known whether the vaccine prevents severe disease, as none of the participants who got Covid-19 in this round of analysis had such cases, said William Gruber, Pfizer senior vice president for vaccine clinical research and development.

Outside researchers said they would need much more data, including the safety information, to assess how good the vaccine is. Assuming the encouraging early results are upheld and the vaccine is approved, use in the general public would still be a ways off, with those at the highest risk likely to get it first.

“So far, it looks like it is promising,” said Peter Jay Hotez, a vaccine researcher and dean of the National School of Tropical Medicine at Baylor College of Medicine. “It helps provide proof of concept that it is possible to make a human Covid-19 vaccine.”

Assuming the vaccine clears the final hurdles, attention will rapidly shift to rolling it out across the world. The challenges will be immense: The companies have agreed to supply deals with the U.S. government and with other countries, but it’s widely expected that front-line medical personnel, essential workers and at-risk groups will receive any authorized shot first.

U.S. states have been working on distribution plans, but many can’t finalize arrangements until it’s clear what shot will be given, as the top candidates have varying requirements for storage and transport. Pfizer’s vaccine, for example, must be kept at ultracold temperatures.

“The rollout of vaccines requires the near-flawless execution of an interconnected chain of processes,” according to an October 21 report from the Boston Consulting Group.

In addition to handling the products, officials will need to mount public education and outreach campaigns, monitor whether vaccines have any safety or efficacy issues once they reach a broader population, and

Two-shot regimen

The Pfizer vaccine is being tested in a two-dose regimen. The trial started in July, and since most participants only received their second dose much more recently, nobody knows how long any protection will last.

However, the strong reading from the first large-scale trial to post efficacy results bodes well for other experimental vaccines, in particular one being developed by Moderna Inc. that uses similar technology. Its big trial could generate efficacy and safety results in weeks. If that study succeeds as well, there could be two vaccines available in the U.S. by around year-end.

Pfizer expects to get two months of safety follow-up data, a key metric required by U.S. regulators before an emergency authorization is granted, in the third week in November. If those findings raise no problems, Pfizer could apply for an authorization in the U.S. this month. A rolling review is in process in Europe.

So far, the trial’s data monitoring committee has identified no serious safety concerns, Pfizer and BioNTech said.

Australian availability

Australian Prime Minister Scott Morrison only last week announced that Pfizer/BioNTech would provide the nation with 10 million vaccine doses, should the vaccines be proven safe and effective.

The Pfizer/BioNTech vaccine has joined another treatment by Novavax, with an agreement for 40 million vaccine doses for Australia, alongside two other promising vaccines, amounting to a total of over 134 million doses.

"By securing multiple COVID-19 vaccines we are giving Australians the best shot at early access to a vaccine, should trials prove successful,” Morrison said.

“We aren’t putting all our eggs in one basket and we will continue to pursue further vaccines should our medical experts recommend them.

“There are no guarantees that these vaccines will prove successful, however our Strategy puts Australia at the front of the queue, if our medical experts give the vaccines the green light.”

Health Minister Greg Hunt said that "health and aged care workers and the elderly and vulnerable will be the first to gain access to a vaccine that’s deemed safe and effective."

Beyond that, "the goal and the expectation is that Australians who sought vaccination will be vaccinated within 2021."

The Australian Government is currently consulting with the states and territories, key medical experts and industry peak bodies on the framework for the initial roll-out of the COVID-19 vaccination program in early 2021.

Leading the race

The positive preliminary data mean the U.S. pharma giant Pfizer and its German partner BioNTech are on track to be first with a vaccine, after signing advance deals with governments worldwide for hundreds of thousands of doses.

About 50 million doses are expected to be available in 2020; the companies have said they should be able to produce 1.3 billion doses – enough to vaccinate 650 million people – by the end of 2021.

However, the companies have signed advance purchase agreements for 100 million doses with the U.S. and double that with the European Union, meaning supply will fall far short of demand at the beginning.

However, most of that would be exhausted if the U.S. and the EU exercise their options.

The vaccine requires extreme freezing for long-term storage, which could complicate distribution, although it can stay at refrigerator temperatures for at least five days.

“It shows that Covid-19 can be controlled,” BioNTech Chief Executive Officer Ugur Sahin said in an interview. “At the end of the day, it’s really a victory of science.”

A new approach

The Pfizer/BioNTech shot relies on messenger RNA technology never before used in an approved medicine. Using mRNA, which essentially teaches the body’s cells to become vaccine factories, allowed it to be developed much faster than a traditional vaccine.

Pfizer had originally planned to conduct a first analysis of trial data after just 32 virus cases had occurred in the trial, which has enrolled volunteers in multiple countries.

Analyzing the data that early proved controversial among medical experts. Other companies working on vaccines planned to wait longer before scrutinizing trial information.

After discussion with U.S. regulators, Pfizer and BioNTech said they recently elected to drop the 32-case threshold and conduct the first analysis at a minimum of 62 cases. The assessment focuses on symtomatic Covid-19 infections, not merely those who test positive.

While Pfizer conducted those negotiations, it paused testing of participant samples for the virus, said Gruber.

By the time Pfizer had made the changes in the trial plan and restarted virus testing a few days ago, some 94 cases had occurred, far more than the trial needed to meet the new threshold.

Pfizer raced to verify the data, which were still blinded to almost everyone at the company beside a few statisticians.

Early on Sunday afternoon, an independent data monitoring committee met in a closed video session to review the results for the first time. Afterward, the panel brought Gruber, Sahin and other company representatives onto the call and told them the vaccine had easily achieved its efficacy goal.

“Everyone is pretty ecstatic,” said Gruber.

Additional reporting by David Flynn