CNN en Español's Dr. Elmer Huerta volunteered for a coronavirus vaccine trial. Here's why

More than 50% of cases of Covid-19 in the United States are African Americans or Latinos, yet they make up only 15% of participants in the first Phase III vaccine trial in the United States, co-developed by biotech company Moderna and the National Institutes of Health.

In fact, National Institutes of Health Director Dr. Francis Collins gave the trial a "C" grade for recruiting minorities.

"From the first week I saw the numbers, and they were not as encouraging as I would have liked," Collins told CNN.

The vaccine could be delayed if the trials don't recruit enough minorities. That's why Huerta, a longtime public health advocate, volunteered for the Phase III trial.

"When you have a clinical trial, it's extremely important for all the races and ethnicities to be represented because sometimes there are differences in toxicity and effectiveness of a medication or vaccine," Huerta said.

"As a Latino I thought it was very important for me to participate."

Huerta, who is a professor of medicine at George Washington University, was elected president of the American Cancer Society in 2007, becoming the first Latino president in its history.

He is also the founder and director of the Cancer Preventorium at the Washington Cancer Institute, and hosts several radio programs with RPP Noticias de Perú focusing on health care and more.

Why are Black and Latinos hardest hit?

There are a number of reasons why Black and Brown communities have higher risks for catching Covid-19 and having more severe reactions that can lead to hospitalization and death.

One factor is that long-standing discrimination and social inequities can lead to limited access to health care and make those populations more likley to have underlying medical conditions such as diabetes and heart disease, according to a US Centers for Disease Control and Prevention report released earlier this month.

There are also structural factors, such as economic and housing policies; and social factors, such as essential worker employment status requiring in-person work, according to the CDC report.

Black leaders agree that it's hard to recruit Black people into the vaccine trials.

"When we Black people hear 'clinical trials,' we think 'we're not going to be researched on,' and that's across economic status and across educational status, not just one sector," Renee Mahaffey Harris, president and CEO of The Center for Closing the Health Gap in Cincinnati, told CNN Senior Medical Correspondent Elizabeth Cohen.

Huerta, who takes questions on his Spanish-language podcast, "Coronavirus: Realidad vs. ficción con Dr. Elmer Huerta," hopes his own efforts will make a difference.

"Please, especially African Americans and Latinos who are underrepresented in this study, consider it," Huerta said. " You are going to get your injection, you will participate, the study lasts for 25 months, and you will be helping yourself and the community."

Half the study participants receive the real vaccine, and half get a placebo. Participants will track if they have symptoms or side effects for about two years.

In the meantime, Huerta has some advice.

"We want to remind you that - until we have an effective and available vaccine or medication - the use of a mask, keeping a distance of at least two meters from other people and washing your hands frequently, are the best measures to fight against infection by the new coronavirus," said Huerta, in a recent podcast.

Practicing one of those safety measures should not cause the others to be neglected, he added. All are necessary to win the fight against this deadly new disease.

Have a question about coronavirus? Tweet @DrHuerta and he may answer your question on his Spanish-language podcast. You can also listen to "Coronavirus: Fact vs. Fiction" in English with CNN Chief Medical Correspondent Dr. Sanjay Gupta.