As new Covid vaccines near U.S. debut, here's what you need to know about the shots

Help is on the way.

This week, two companies released more news on their Covid-19 vaccines as they prepare to seek regulatory clearance, flashing signs of hope that the U.S. could soon have more weapons against the pandemic. But with fresh reasons to be hopeful also came signals of caution, as the not-yet-authorized vaccines appeared to be less effective against some rapidly spreading strains of the virus.

Biotech firm Novavax said Thursday that its vaccine was more than 89% effective in protecting against the disease in its phase three clinical trial conducted in the United Kingdom. And Johnson & Johnson added Friday that its single-dose shot was 66% effective overall in protecting against Covid-19. 

The introduction of two more vaccines could significantly bolster the world’s arsenal of tools to drive back the virus and bring the pandemic to an end. And while J&J’s vaccine appears to be significantly less effective in preventing disease than Moderna’s and Pfizer-BioNTech’s, officials said it’s still effective enough to prove useful and the fact that it only requires one shot is a clear advantage.

With more vaccines entering the fray, here’s what you need to know as you prepare to get your shot:

Pfizer’s vaccine has been authorized by the Food and Drug Administration for use in people age 16 and older, while Moderna’s vaccine has been authorized for people 18 and up.

J&J’s vaccine hasn’t been authorized yet. The company is expected to submit an application for emergency use authorization to the U.S. agency next week. The FDA review process is expected to take a few weeks, and the vaccine could be distributed across the U.S. as early as next month.

Meanwhile, it’s unknown when the Novavax vaccine will be authorized for use in the U.S. Its phase three trial, the results of which were published Thursday, was conducted in the United Kingdom, and it’s unclear if that will be enough for U.S. authorization. The company began a late-stage trial with 30,000 people in the U.S. and Mexico in late December.

With supply so constrained, states are rationing doses to those deemed most vulnerable and essential to society. While there is federal guidance on who should get the shots first, many states are charting their own course. But with the slower-than-expected rollout, the federal government urged states to open up eligibility to everyone 65 and older.

More than 48.4 million doses of vaccine have been distributed in the U.S. so far, according to data from the Centers for Disease Control and Prevention. Considering the two currently authorized vaccines are two-dose regimens, the U.S. would need more than 660 million shots to inoculate the entire public with the currently available vaccines.

Earlier this week, President Joe Biden announced plans to purchase an additional 200 million doses of the vaccines, including 100 million from Moderna and 100 million from Pfizer. That would bring total U.S. supply of those two vaccines to 600 million doses, but the companies are still working to ramp up the pace of production. Pfizer has said it will deliver 120 million doses, and Moderna has promised 100 million by April.

The introduction next month of J&J’s one-shot vaccine could ramp up supply in the U.S., which has ordered 100 million doses from J&J to be delivered by the end of June. Novavax has agreed to deliver 100 million doses of its vaccine to the U.S. if it’s authorized.

Manufacturers and the U.S. government are studying how effective the current vaccines are against new variants of the virus. One variant in particular, the B.1.351 strain that’s become dominant in South Africa, is causing concern among health officials.

The global trials of the Novavax and J&J vaccines give some indication about how those vaccines will hold up against new strains. Novavax said its vaccine proved just 49% effective among 44 Covid-19 cases in South Africa, where 90% of the cases were associated with the troubling new variant. And J&J said its vaccine was 57% effective in the South African arm of its trial.

Dr. Paul Offit, a member of the FDA’s Vaccines and Related Biological Products Advisory Committee, told CNBC the new strains are not a huge problem yet, but it’s important for drugmakers to prepare for the possibility that the virus could mutate enough to evade the protection of the current vaccines.

“Prepare for it. Sequence these viruses. Get ready just in case a variant emerges which is resistant” to the vaccine, he said.

Both Pfizer and Moderna have already said they’re working on a booster shot for their vaccines that will hold up better against the B.1.351 strain.

The first two vaccines authorized in the U.S. set a lofty standard for the others to follow. Pfizer’s data showed that its vaccine was 94% effective in preventing the disease, while Moderna’s read out at 95% efficacy.

J&J said its vaccine was 72% effective in preventing the disease in the U.S., but added that it was 85% effective in preventing people from becoming severely ill with Covid-19. White House health advisor Dr. Anthony Fauci noted later Friday that the most important finding of the J&J vaccine data is that the single shot may keep people out of hospitals and prevent severe illness.

“The first thing people do is compare a 72% efficacy with the previously reported in other trials of 94% to 95%. That is true,” Fauci said at a White House press briefing Friday, adding that the more important figure to look at is the 85% efficacy in preventing severe sickness.

“The most important thing — more important than whether you prevent someone from getting aches and a sore throat — is preventing people” from getting severe disease, Fauci had said earlier on a call with reporters. “That will alleviate so much of the stress and human suffering and death in this epidemic.”

But with supply limited and appointments hard to come by, public health specialists are urging people to accept whichever vaccine is available to them, rather than wait for their vaccine of choice.

“I don’t think in a public health crisis, we should be picking,” said Dr. Carlos del Rio, a professor at Emory University School of Medicine. “I think in a public health crisis, you take what there is.”

As supply of vaccine doses ramps up and new players enter the fray, many Americans still won’t be able to get a shot for months. Health officials are urging people to take steps to drive down the level of spread, in the meantime, to prevent more new strains of the virus from emerging.

Viruses are like nature’s artificial intelligence, William Haseltine, president of the think tank ACCESS Health International and a former Harvard Medical School professor, told CNBC. As the virus spreads, it makes huge numbers of copies of itself, and each version is a little different from the one before it.

Those copies allow the virus to adapt to its environment. As they spread, they can learn how to penetrate into humans better and make themselves more transmissible, like the variants of concern first reported in the U.K., South Africa and Brazil. That’s part of the reason why global health experts have pushed for people to dent Covid-19’s spread through public health measures, such as social distancing, washing hands and wearing a face mask. That would give the virus fewer opportunities to mutate, and it would buy time until a vaccine can be rolled out.

“What this virus is telling us is if we don’t control it through public health, we’re sunk for a couple more years and maybe for a much longer time. That is a big message,” Haseltine said. “Don’t rely on the vaccines, don’t rely on the drugs. This virus can outwit them.”

Dr. Jay Butler, the CDC’s deputy director for infectious diseases, said on Friday that current modeling suggests that 70% to 75% of people would need to be vaccinated for the population to reach herd immunity. However, if a faster spreading virus were to become the dominant strain, it would likely push that percentage to as high as 85%, he said.

“Looking down the road, I think it emphasizes again the importance of ongoing work in community mitigation, as well as the importance of using the vaccines that we have available now and in the near future,” Butler said on a conference call organized by the Infectious Diseases Society of America.