Vaccines that are sprayed into the nose or inhaled may have other practical benefits.
The Covid-19 vaccines closest to the finish line are designed to be injected into the arm. Researchers are looking to see if they can get better protection against inoculations that fight off the virus at its point of attack – the nose and mouth.
Most vaccines tested on humans require two injections to be effective, and developers are still unsure of how to prevent infections. Scientists hope to generate superior immune responses with inhaled vaccines that directly target cells in the respiratory tract invaded by the virus.
An alternative to conventional, sprayed and inhaled vaccines under development in the United States, Britain and Hong Kong could play an important role in helping society escape restrictions that have shaken economies and daily life. One of their goals is to prevent the pathogen from growing in the nose, where it can spread to the rest of the body and to other people.
“Local immunity is important,” said Frances Lund, an immunologist at the University of Alabama at Birmingham working with Altimmune Biotechnology Inc. on early stage nasal inoculation. “The vaccines which can be delivered to generate that will have certain advantages over vaccines which are delivered systemically.”
Most of the early vaccine developers focused on a familiar route – injections – considered the fastest to protect the world from disease. Manufacturers of inhaled vaccines rely on some of the unique characteristics of the lungs, nose and throat, which are lined with mucous membranes. This tissue contains high levels of immune proteins, called IgA, which provide better protection against respiratory viruses.
Activating these immune weapons, they theorize, can protect the deeper areas of the lungs where SARS-CoV-2 does the most damage. They can also improve the chances of vaccines blocking transmission.
“The first generation of vaccines will probably protect a lot of people,” said Michael Diamond, an infectious disease specialist at Washington University in St. Louis. “But I think it’s the second and third generation vaccines – and maybe intranasal vaccines will be a key part of that – that will ultimately be needed. Otherwise, we’ll continue to have community transmission.”
In a study on mice in August, Diamond and his team found that administering an experimental vaccine through the nose created a strong immune response throughout the body; the approach was particularly effective in the nose and respiratory tract, preventing infection from taking hold. India’s Bharat Biotech and St. Louis-based Precision Virologics secured the rights to the single-dose technology last month.
Vaccines that are sprayed into the nose or inhaled may have other practical benefits. They do not require needles, may not need to be stored and shipped at low temperatures, and may reduce the need for health workers to administer them.
“When you think about trying to provide this across the world, if you don’t need an injectable vaccine, your adherence increases because people don’t like to be vaccinated,” according to Lund, the researcher based in China. Alabama. “But second, the level of expertise required to administer this vaccine is very different.”
Altimmune, based in Gaithersburg, Md., Plans to start human testing with a nasal vaccine in the fourth trimester after positive studies in mice. Scientists at the University of Oxford, where a promising vaccine in development at AstraZeneca Plc has been designed, and Imperial College London are also planning studies on slightly different inhaled vaccines.
Experimental immunizations in Britain would be delivered through a mouthpiece in an aerosol, similar to some asthma therapies. Imperial researchers find that administering influenza vaccines by nasal spray can protect people from the disease and help reduce transmission; they want to explore whether this is also the case with SARS-CoV-2. AstraZeneca manufactures the FluMist nasal spray vaccine.
According to Robin Shattock, an infectious disease specialist at Imperial College, data from inhaled Oxford vaccine studies could come early in the new year, followed by second-quarter Imperial results.
“We don’t know if it will work well, but if it does, it could be very important,” he said in an interview.
Imperial College has conducted studies in recent months on a Covid vaccine using RNA technology that would be administered by conventional injections and plans to expand its trials to 20,000 people by the end of the year. Oxford, one of the pioneers in the global quest for inoculation, is in the final stages of testing a vaccine that uses a harmless virus to transport the pathogen’s genetic material into cells to generate an immune response. Both techniques can be conducive to inhalation, Shattock said.
“It’s a virus that spreads through your airways, so if you want a vaccine that will really prevent infection and transmission, you want to have an antibody response in your nose, in your lungs,” Shattock said. “The most effective way to induce this is to inoculate by this route.”
Researchers in Hong Kong are targeting an intranasal vaccine that would simultaneously provide protection against influenza and Covid-19. The first phase of human testing will begin next month, said Yuen Kwok-Yung, director of infectious diseases in the department of microbiology at the University of Hong Kong.
The ambition is to deliver the “vaccine of choice” as the world seeks to build on the first wave of products, he said.
Questions about the sustainability of nasal vaccines have not yet been resolved and are at an early stage. Despite the benefits, the delivery arrangements are also more complex, according to Nick Jackson, head of programs and technology at the Coalition for Epidemic Preparedness Innovations.
“A needle and syringe work great,” he says.
Still, the researchers said targeting the airways could pay off down the road. The Oslo-based CEPI funded the Hong Kong project and is open to new investments in vaccines that take unconventional approaches as part of an effort to deliver billions of doses to all corners of the world, Jackson said.
“Whether it’s our vaccine or one that goes intransasally that is actually successful in disrupting transmission and disrupting the pandemic, I tip my hat,” Diamond said. “If we’re helping by getting or pushing these companies to think about an alternate path for what could be a successful platform, then we’ve done our job.”
(Except for the title, this story was not edited by GalacticGaming staff and is posted from a syndicated feed.)
