Hopeful news about a Covid-19 vaccine developed by US government researchers and Moderna Inc has buoyed expectations – and markets – on the potential for a preventive measure against a global pandemic that has killed more than half a million people and upended daily life.

Moderna first announced its vaccine, backed by the National Institute of Allergy and Infectious Diseases, prompted an immune response in 45 adults in May.Advertisementhttps://tpc.googlesyndication.com/safeframe/1-0-37/html/container.html

On Tuesday, it published a fuller look at the data in a report in the New England Journal of Medicine.

But experts cautioned against heightened expectations about the Moderna vaccine, one of many being worked on around the world, as it is still in the early stages of development.

The report was “certainly no cause for celebration”, said Dr Peter Hotez, dean for the National School of Tropical Medicine at Baylor College, and a vaccine researcher in Houston, Texas. “But [it is] provocative enough that it’s worth looking at in a phase 3 trial.”

“These are small studies,” Hotez added. “This is why you have to do the big phase 3 clinical trials in 10,000 to 30,000 patients,” he said.

The news comes as cases surge across America’s Sun Belt, a region spanning southern California to Florida, and researchers not involved in the research noted challenges lay ahead.

Florida has crossed an ominous threshold with more than 300,000 Covid-19 cases. Republican Oklahoma Governor Kevin Stittannounced he had tested positive for Covid-19, the first known case in a US governor.

And America’s top infectious disease expert, Dr Anthony Fauci issued a pointed call for the White House to stop the “nonsense”, referring to criticism of his efforts, in an interview with the Atlantic.

More than 150 laboratories worldwide are working to develop vaccines for Covid-19, most in early phases. Moderna’s vaccine is one of 23 in human trials, and a handful entering phase 3 of clinical trials.Advertisementnull

Moderna is one of five pharmaceutical companies that have received billions from the US government, in a vaccine development initiative called Operation Warp Speed. Later this month, Moderna and a handful of other laboratories will begin recruiting tens of thousands of volunteers to take the vaccine.

Coming studies must balance safety and efficacy. In other words, how large a dose of the vaccine is necessary to make it effective, while also minimizing unpleasant and potentially harmful side effects?

“The safety and immunogenicity data in this preliminary report are promising, and they support continued development of this vaccine,” said Dr Penny M Heaton, the CEO of the Bill and Melinda Gates Foundation Medical Research Institute, in an editorial that accompanied Moderna’s study. “However, we must bear in mind the complexity of vaccine development and the work still to be done before Covid-19 vaccines are widely available.”

Notably, Moderna researchers abandoned a higher dose of the vaccine because it did not appear to provide a better immune response and produced worse side effects, including headache, chills, fever and fatigue.

At the same time, researchers must contend with Covid-19 antibody tests that can be unreliable. It is also unclear how long an immune response might last. One year? Six months? The Moderna study reported on findings after 57 days, though researchers will follow participants for one year.Advertisementhttps://b2b78fd607c2a22c6a35ac95361f5b3f.safeframe.googlesyndication.com/safeframe/1-0-37/html/container.html

In addition, older people most vulnerable to Covid-19 may face special challenges. Older people may need more of the vaccine because their immune systems in general are less responsive. The same phenomenon takes place in influenza vaccines, Heaton wrote.

In light of so many unknowns, fundamental questions remain about when and if a vaccine will be developed for Covid-19, and what it will look like once it is approved.

“Everyone’s been saying, ‘We’re going to have these vaccines by the fall or the end of 2020,’ and I keep saying – no, we’re going to need those Phase 3 studies,” said Hotez. “We won’t have the information until third quarter of 2021, and even that would be a world land speed record.”

The news has also renewed criticism about Operation Warp Speed and how to distribut an approved vaccine equitably in a world where taxpayers subsidized its development and demand will outstrip supply many times over.

“We are now two months into Operation Warp Speed and people across the country still have no idea if the drug company executives Trump put in charge of it secured any assurances regarding access and affordability of vaccines developed with taxpayer dollars,” said Eli Zupnick, spokesman for Patients Over Pharma, a group critical of pharmaceutical companies

(Source :The Guardian)