Harvard scientists are developing a coronavirus vaccine specifically for those most vulnerable: the elderly

• Various factors affect the effectiveness of a vaccine, including the age and sex of the person receiving it.
• Researchers at Boston Children's Hospital are working to develop an age-specific coronavirus vaccine to protect those most vulnerable: the elderly.
• They're testing different coronavirus vaccine formulations on human tissue outside of the body, which contains cells from people of different ages.

More than 100 teams around the world are racing to develop a coronavirus vaccine. Dr. Ofer Levy and a group of Harvard Medical School researchers are among them, but the vaccine they're working on is a little different. It's specifically designed for those most vulnerable to the disease: the elderly.

"Most vaccines are developed with a one-size-fits-all concept," Levy told Business Insider. "Academic centers and companies typically develop a vaccine assuming that you will respond to the vaccine the same way, whether you're a man or a woman, whether you're young or elderly, whether you live in the US or Africa, whether you give the vaccine in the summer or winter, whether you give it in the morning or the evening."

But various factors can impact how much protection a vaccine confers, including age. Take the flu, for example, which is more deadly for older people with weaker immune systems.

"Many elderly individuals, unfortunately, do not respond optimally to influenza vaccine," Levy said. "They should take it — it's safe and it has some effectiveness. But we wish it was more effective, because up to 30%, 40% of elderly individuals may be non-responders to the flu vaccine and that's because the immune system of the elderly weakens."

Vaccine development is a long and expensive process, and that is all the more true for attempts to make targeted vaccines for specific groups. But Levy's lab is researching the concept by testing vaccine formulas on human tissue outside of the body, which is designed to model newborn, middle-aged, and elderly immune system responses.

"In our minds, vaccines are not one-size-fits-all," Levy said. "They may be one-size-fits-none-particularly-well."

As for a timeline, Levy said that a one-size-fits-all vaccine will become available before the one he wants to create. Several pharmaceutical and biotech companies have said they're aiming to have a shot ready for emergency use in the fall.

"We're not going to be the first vaccine into trials," he said, but added, "we hope to have things that could go into humans, let's say, within a year or so."

'Modeling the human immune system outside the body'

Levy works with the Precision Vaccines Program at Boston Children's Hospital, which is affiliated with the Harvard Medical School. His laboratory focuses on developing "next-generation" vaccines to protect specific populations.

The lab uses a technology that builds human tissue outside of the body; it received a patent earlier this month. The researchers simulate age differences by collecting blood samples from people of all ages and adding their white blood cells to the tissue. They have already collected samples from elderly volunteers for their coronavirus vaccine research.

The white blood cells recognize antigens like viruses and develop immune responses to them. Comparing this process across tissue samples enables the scientists to see how different immune systems respond to various vaccine formulations. That allows the lab to learn what might be most effective for whom before the clinical trial phase.

"It's not going to be possible to do large, phase three, multi-thousand person studies of every single combination in every type of population," Levy said. "That's where modeling the human immune system outside the body could be key, because it may allow us to accelerate and de-risk vaccine development."

A personalized medicine approach to vaccines

Before the coronavirus pandemic, Levy's lab was working on a vaccine for whooping cough that offered longer-lasting immunity and a vaccine for the respiratory syncytial virus, which is the number-one cause of infant hospitalization in the US. The researchers were also trying to develop an HIV vaccine that's more effective for newborns.

"We anticipate that, in the future, there'll be different vaccine formulations for a baby, a man versus a woman, an elderly person," Levy said. "It's this whole notion of personalized medicine, but brought to vaccinology."

After the coronavirus started spreading, the program switched its focus.

"I was biking home from work, and there's a newspaper machine that dispenses the news in Chinese, and it had a headline, a very dramatic headline, big, bold letters, but I don't read Chinese," Levy said. "But it had the word SARS in it in English, and that caught my eye. And then, of course, it became more and more clear with the Wuhan outbreak, and so we said, 'Well, our entire program is really well positioned to help with this.'"

Developing effective vaccines for the elderly

Vaccines contain a weakened form of the antigen they're meant to protect the body against, so that the immune system can recognize the virus and neutralize it. Molecules called adjuvants can be added to a vaccine to improve the immune response it elicits.

Levy offered four ways that pharmacological or immunological agents can help: They can convert an insufficient response into a more robust one; enhance the range of immune responses; make immunity last longer; or allow producers to include less of the antigen in each dose, thereby enabling them to make higher quantities of a vaccine more affordably.

"We've screened hundreds and hundreds of thousands of molecules," Levy said. "We're screening them against elderly human cells, and you'll find different combinations of adjuvants are optimal in different age groups."

The downside of adding adjuvants to a vaccine is that it makes the formulation more complicated. But Levy believes the benefits are worth it, and says the way his lab tests adjuvants in tissue minimizes risk.

In addition to the lab's own vaccine development, Levy added, companies and academic teams have been sending their coronavirus vaccine formulations for Levy's group to test.

"We're natural partners for other groups because we have these unique systems to test vaccines outside the body, so everybody wants to send us their adjuvants, their formulations, to test, so we can compare, head-to-head," Levy said.

He added that the lab has also ordered elderly mice to study, but said a vaccine "doesn't go into the mice until it first goes into a human system outside the body."

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