In the race to create a vaccine s, some researchers are testing new approaches they hope can ultimately produce vaccines in months rather than years.
The number of people diagnosed with COVID-19 each day has continued to increase as more tests have been administered in many countries. Each country declared the coronavirus outbreak a public health emergency, and many have implemented restrictions on travel, business and public gatherings.
Why it matters: The global COVID-19 outbreak is a harsh reminder of the urgent need to be able to vaccinate large swaths of the population fast — in this pandemic and the next.
What's happening: The world is pinning its hopes on a vaccine for COVID-19 to save lives, return to normal and emerge from an economic recession.
Experts estimate it could take at least 12–18 months for a vaccine to be widely available, with glimmers of hope for some limited availability sooner tempered by a reality that vaccines typically take multiple years to develop.
The state of play: There are at least 92 vaccines under development for COVID-19.
22 of those are experimental DNA- or RNA-based vaccines, which provide the most hope for speedy development.
"These technologies will be pushed to limits they’ve never been pushed to before and we’ll see how they perform," says Harvard Medical School's Dan Barouch of DNA and RNA vaccines. "We’ll know a lot more about the status of these technologies at the end of COVID-19."
Oxford University is launching a human trial of a potential coronavirus vaccine, with the daunting aim of making a successful jab available to the public later this year. Of the more than 100 research projects around the world to find a vaccine - described by the United Nations as the only route back to "normality" - seven are currently in clinical trials, according to the London School of Hygiene and Tropical Medicine.
Background: For more than 200 years, vaccines have worked by introducing the body to either a version of the virus itself that doesn't cause disease or an antigen that's typically a protein on the virus surface. Both prime the immune system and spur it into action should someone encounter the virus.
Those approaches gave the world effective vaccines for polio, measles, hepatitis B and other diseases.
But each time, researchers have to develop anew the biological machinery — cells and reactor conditions — needed to manufacture the vaccines.
But, this simply takes too much time during times of crisis, per Johns Hopkins Center for Health Security's Amesh Adalja.
Vaccination is the most successful medical approach to disease prevention and control. The successful development and use of vaccines have saved thousands of lives and large amounts of money. In the future, vaccines have the potential to be used not only against infectious diseases but also for cancer as a prophylactic and treatment tool, and for the elimination of allergens
What's new: DNA and RNA vaccines are a potential avenue for speeding up vaccine development.
Instead of delivering the antigen, these vaccines introduce the DNA or RNA sequence that encodes the antigen and it is produced by the body's cells. (RNA acts as an information-carrying intermediary between DNA and the protein it encodes.)
When a new virus emerges, the idea is an antigen from it could be quickly sequenced and the genetic code plugged into an already-approved vaccine platform with an existing tried-and-true manufacturing process. That would eliminate the long process of developing a line of cells for producing the vaccine.
BUT: No RNA and DNA vaccines have been approved for humans — for any virus.
DNA vaccines, which have been in development for two decades, sometimes struggle to cause a strong immune response to a virus.
RNA vaccines are a newer approach, and delivering them to the right cells can be a challenge.
Vaccines for hepatitis C, malaria and other viral diseases are being developed with the platform. Biotechnology company Moderna created an RNA vaccine for Zika during the outbreak in 2015. But the virus largely went away and the vaccine wasn't tested in an outbreak.
Several teams are working on RNA vaccines for SARS-CoV-2, the virus that causes COVID-19, including Moderna and the NIH's Vaccine Research Center. Their RNA vaccine is in Phase I trials in three sites, testing the safety of doses and whether it can induce an immune response in humans.
In its first phase, half of 1,112 volunteers will receive the potential vaccine against COVID-19, the other half a control vaccine to test its safety and efficacy. The volunteers are aged between 18 and 55, are in good health, have not tested positive for COVID-19 and are not pregnant or breastfeeding. Ten participants will receive two doses of the experimental vaccine, four weeks apart.
Meanwhile, Barouch and his collaborators at Johnson & Johnson are taking a different approach, using a non-infectious version of an adenovirus — a common cold virus— to shuttle DNA for an antigen into the body's cells.
The experimental platform was developed for an Ebola vaccine and Barouch says, unlike RNA and DNA vaccines, it is grown in cells and has a proven ability to scale up.
The Oxford vaccine is based on a chimpanzee adenovirus, which is modified to produce proteins in human cells that are also produced by COVID-19. It is hoped the vaccine will teach the body's immune system to then recognise the protein and help stop the coronavirus from entering human cells.
The adenovirus vaccine is known to develop a strong immune response with a single dose and is not a replicating virus, so cannot cause infection, making it safer for children, the elderly and patients with underlying diseases such as diabetes.
The big picture: Testing vaccines quickly and not relying on cells to manufacture them would be a game-changer for future pandemics.
Moving vaccine production out of cells could be one component for decentralized, local production of medicine, vaccines and diagnostics for responding to pandemics and addressing antibiotic-resistant microbes, he says.
Bottom line: This global pandemic is a testbed for the next generation of vaccine technologies.