More Coronavirus Vaccine Efforts Move Toward Human Trials

Moderna and Inovio are pioneering a different approach to their vaccines.

Moderna uses RNA technology, while Inovio has developed DNA technology to package the genetic code of coronavirus spike proteins, which make up the crown around the virus and help it latch on to cells. This approach has the advantage of being able to move to trials faster than vaccines that require the production of viral proteins or a weakened version of the actual virus to induce an immune response. But the technology is still unproven. There are no approved RNA or DNA vaccines for any disease.

Dr. Hotez’s team and Johnson Johnson, on the other hand, are relying on technology that is more similar to Novavax’s approach because it has been used successfully to create other vaccines in the past, including one for Ebola that has been registered in Europe and used in the recent epidemic in the Democratic Republic of Congo.

Some countries already have the manufacturing capabilities that will be needed to scale up vaccine production and keep costs low if everything goes well.

“It’s not very sexy, but it’s a reliable approach. We know that it works,” Dr. Hotez said.

For now, the first stage of clinical trials for each potential coronavirus vaccine must focus on how safe or toxic the vaccine may be at different dose levels. Researchers will carefully collect the medical histories of volunteers participating in the trials and track their antibody levels, liver enzymes and other indicators of emerging side effects.

One concern is that the vaccines may inadvertently cause a phenomenon known as disease enhancement, in which vaccinated people develop more severe inflammation and disease than those who have never been vaccinated. Studies of early SARS and MERS vaccines noted this troublesome complication in some animal models.

“If everything looks good and the vaccine appears to be safe, then we’ll go on to trials with much bigger numbers and look at the vaccine efficacy,” said Dr. John Ervin, who is leading the Inovio clinical trial in Kansas City, Mo.

In parallel, companies are planning to continue further animal testing, as well as investing in manufacturing capacity both in the United States and abroad. They will need millions of doses for additional clinical trials and even more if a vaccine eventually goes to market.

Article source: https://www.nytimes.com/2020/04/08/health/coronavirus-vaccines.html