MESO action tonight, page-3019

Very few people said they would take the vaccine if it became available since they don't trust it. Was this only under a Trump presidency and would this fear be magically overturned under a Biden presidency? There are still many questions that need to be answered and I would not assume that this vaccine trial is a roaring success unitl the final data are in, although in saying that, i've always felt BioNtech's vaccine would be successful.

https://www.nature.com/articles/d41586-020-03166-8

Questions remain

What’s missing, say Topol and other scientists, are details about the nature of the infections the vaccine can protect against — whether they are mostly mild cases of COVID-19 or also include significant numbers of moderate and severe cases. “I want to know the spectrum of disease that the vaccine prevents,” says Paul Offit, a vaccine scientist at the University of Pennsylvania who sits on a US Food and Drug Administration advisory committee that is set to evaluate the vaccine next month. “You’d like to see at least a handful of cases of severe disease in the placebo group,” he adds, because it would suggest that the vaccine has the potential to prevent such cases.

It’s also unclear whether the vaccine can prevent people who show no or only very mild symptoms of COVID-19 from spreading the coronavirus. A transmission-blocking vaccine could accelerate the end of the pandemic. But it will be difficult to determine if the Pfizer vaccine, or others in late-stage trials, can achieve this, says Krammer, because it would involve routinely testing trial participants. “You can't do that with 45,000 people,” he says.

Another missing detail is how well the vaccine works in different groups of trial participants. “We don't know yet if it works in the population that needs it most which are elderly,” says Krammer. Because of the small number of cases it will accrue before ending, the Pfizer trial is unlikely to determine conclusively the vaccine’s efficacy in subgroups such as over-65s or African Americans, says Offit. But he adds that if the trial enrolled enough participants from such groups, it may be possible to generalize the vaccines’ likely effectiveness in these groups from its overall efficacy. In the press release, Pfizer and bioNtech reported that 42% of participants had “racially and ethnically diverse backgrounds”.

Lasting immunity?

One key unanswered question is how long the vaccines’ effectiveness will last. Based on when the trial started and previously published data on immune responses in early-stage trials, many trial participants are likely to still have high levels of protective antibodies in their blood, says Rafi Ahmed, an immunologist at Emory University in Atlanta, Georgia. “To me, the main question is what about six months later, or even three months later,” he says.

There will be a chance to answer that question if the trial continues for several more months, says Ahmed. Answers could also come from analysing the immune responses of people who took part in early-stage trials of the Pfizer vaccine, some of whom may have been given the vaccine up to 6 months ago. And although little is known about the vaccine’s long-term effectiveness, that is unlikely to hold up its use, says Ahmed. “I don't think we should say, ‘Well, I’ll only take a vaccine that protects me for five years.’ I mean, that could be crazy.”

The results are a boost for other COVID-19 vaccine developers. That includes a vaccine being developed by Moderna, a Cambridge, Massachusetts biotech, and the US National Institute of Allergy and Infectious Disease, in Bethesda, Maryland, that is also comprised of mRNA, says Krammer. “I expect Moderna stocks will go up today.”

Shane Crotty, a vaccine immunologist at the La Jolla Institute for Immunology in California, thinks that Moderna isn’t the only developer that should celebrate Pfizer’s preliminary results. Several other candidate vaccines triggered immune responses similar to those elicited by Pfizer’s vaccines in early-stage trials, so they should work well, too.

One thing about Pfizer’s vaccine is certain: regulators will soon deem whether it’s ready for roll-out. The company said it would seek an emergency use authorization from FDA around the third week of November, at which point participants will have been followed for an average of 2 months — an FDA safety requirement for COVID-19 vaccines.

And although researchers want to see the data behind Pfizer’s vaccine trial, they are prepared to accept caveats that come with them. “Right now we need a vaccine that works,” says Krammer, even if it works only for a few months or doesn’t stop transmission. “That's what we need in order to get halfway back to normal.”