The quest for a “warm” COVID-19 vaccine

The best solution to the cold chain problem? Eliminate the need for it altogether.

A safe and effective COVID-19 vaccine alone won’t be enough to beat the pandemic. We also need to be able to get that vaccine to people — and that could be a logistical nightmare.

Heat can degrade vaccines, so most vaccines must be transported and stored via a temperature-controlled supply chain, known as a “cold chain.”

That alone can be an insurmountable hurdle in some less-developed or rural places, and two of the most promising vaccines — Moderna’s and Pfizer’s — must be transported and stored at very cold temperatures.

Pfizer’s requirement is so extreme (-94 degrees Fahrenheit) that it might not be a viable option for up to two-thirds of the world’s population.

To overcome this issue, some researchers are working to develop a warm COVID-19 vaccine, one that could be transported and stored at room temperature — and usually, that means changing how the vaccine is administered, too.

A Freeze-Dried COVID-19 Vaccine

Researchers at the Indian Institute of Science (IISc) are developing a warm COVID-19 vaccine that triggered a “strong immune response” in guinea pigs, according to a recent peer-reviewed study.

A promising animal study isn’t enough to set the COVID-19 vaccine apart, but the fact that it remains stable for up to 30 days at 98.6 degrees Fahrenheit — and can be freeze-dried and stored at temperatures as high as 200 degrees Fahrenheit — is.

“It is still being tested on guinea pigs and may take more than a year to be approved,” K. Srinath Reddy, president of the Public Health Foundation of India, told the Guardian. “But if it comes through, you’ll have a heat-stable vaccine that can be turned into a powder and easily transported across the country.”

An Inhalable Vaccine

The IISc team’s warm COVID-19 vaccine is designed to be rehydrated and injected, but other groups are developing ones that wouldn’t need needles at all.

Biopharma company Altimmune, for example, is working on a nasal spray vaccine that it expects to have “extended stability at room temperature.” In a study published on the preprint server bioRxiv, the company reported that the vaccine “prompted a strong immune response” in mice.

You won’t need specially trained medical personnel to deliver the vaccine.

Altimmune still has a lot of research to conduct, but if the vaccine proves safe and effective, the ability to deliver it without injections could be a boon even in places with a reliable cold chain.

“When you’re thinking about trying to deliver that across the world, if you don’t need to have an injectable vaccine, your compliance goes up because people don’t like getting shots,” Altimmune researcher Frances Lund told Bloomberg in October. “But secondly, the level of expertise needed to administer that vaccine is significantly different.”

In other words, without a syringe, you won’t need specially trained medical personnel (also in short supply) to provide the vaccine.

A Patch For the Coronavirus

In April, researchers at the University of Pittsburgh announced their development of a warm COVID-19 vaccine that requires a lot of needles — but they’re really, really tiny.

This vaccine, PittCoVacc, is a fingertip-sized patch covered in 400 microneedles made from sugar and synthetic bits of the coronavirus. Place the patch on the skin and the needles dissolve, delivering the vaccine.

In mouse studies, PittCoVacc prompted the creation of enough antibodies to neutralize the coronavirus, and the researchers are now awaiting approval to test their vaccine in humans.

Not only is the delivery process painless, the microneedle patches can be stored at room temperature — eliminating the need for a cold chain.

“For most vaccines, you don’t need to address scalability to begin with,” co-senior author Andrea Gambotto said in a press release. “But when you try to develop a vaccine quickly against a pandemic, that’s the first requirement.”

An Easy Pill to Swallow

Biotech company Vaxart might be responsible for the easiest-to-distribute warm COVID-19 vaccine candidate — and it’s also one of the furthest along in development.

We dream that the vaccine is going to be sent by mail or even drone.


Sean Tucker

The company’s VXA-CoV2-1 is a room-temperature-stable COVID-19 vaccine administered via a tablet.

In a hamster challenge study, two doses of the vaccine prompted a robust immune response and significantly decreased the amount of the virus in the animals’ lungs. In October, Vaxart kicked off a phase 1 trial of the tablet in humans.

“A tablet vaccine like ours…we dream that it’s going to be sent by mail, or even drone or some other delivery service, because it is room temperature stable, so you don’t have to deal with the problems with the cold-chain,” founder Sean Tucker told the Guardian.

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