Is a vaccine for coronavirus on its way, and what are the challenges?
The first potential vaccine for COVID-19, called mRNA-1273, has started human clinical trials. This is a crucial step in drug development and means that healthy volunteers will test the vaccine’s safety before it is tested in a larger group of people.
The speed at which this has taken place is remarkable. Usually, getting a potential vaccine through all stages of development to start human trials takes years. However, mRNA-1273 – developed by Moderna Therapeutics – entered clinical trials just 63 days after scientists had deciphered the genetic code of the virus1.
Despite this remarkable progress, it is important to remember that treatments and vaccines must be tested in a sufficient number of people to ensure they are safe and effective. We expect global health authorities to maintain the high hurdle for safety and efficacy they demand of all approved therapies. The reason for this is clear – a vaccine that is not properly tested could cause unexpected side effects and harm people if rolled out too quickly and put even greater pressure on global healthcare resources. Therefore, health officials have said they expect a vaccine is still 12 to 18 months away from being approved2.
How is a vaccine being developed, and who is developing it?
There are many researchers and pharmaceutical companies working on potential vaccines for COVID-19. Richard Hatchlett, chief executive of the Coalition for Epidemic Preparedness Innovations – a body that finances and coordinates the development of new vaccines – said recently that his organisation had received 48 applications “from all over the world following our call for proposals in February”.3 Pharmaceutical companies that have announced they are working on COVID-19 vaccines include Sanofi4, GSK5 and Johnson & Johnson6. In my opinion, two of the most advanced are those being developed by Moderna and co-developed by BioNTech and Pfizer.
Moderna, as mentioned above, is developing mRNA-1273, which has started phase one human clinical trials in healthy volunteers. Unlike many traditional vaccines, which are a weak form of a particular virus, this is a modern form of vaccine using genetic material.
This particular potential vaccine injects a small piece of genetic material – called mRNA – into the body, that is the genetic blueprint to make a protein on the virus’s surface. It is then absorbed by immune cells called antigen-presenting cells (APCs). APCs have the immune-stimulating components of the vaccine on their surface, kickstarting an immune response that allows the body to identify and respond to the virus more quickly if a person becomes infected.
BioNTech and Pfizer have announced they are collaborating on a similar mRNA-based vaccine that could enter clinical trials by the end of April.7
What other potential treatments are being developed?
As well as vaccines, antiviral drugs are being tested to see if they can be used to treat patients with coronavirus. For example, Gilead’s drug remdesivir is being tested in multiple trials, including two phase three trials in Chinese COVID-19 patients8. Data is expected from these trials between now and the end of April. We will be looking for an indication that the drug can reduce the clinical severity of the virus, such as reducing a patient’s need for mechanical ventilation, while also having acceptable side effects. If this is the case, we may see global drug regulators act quickly to approve the medicine’s use. Furthermore, investors in global capital markets may become more confident that healthcare professionals can effectively treat the disease, even if a vaccine is not yet available. Many other antiviral medicines, both approved and investigational, are being tested in trials globally.
A number of studies are looking at whether anti-inflammatory drugs could be useful in reducing the symptoms and knock-on effects of COVID-19 in critically ill patients. One small study of 20 patients in China, for example, appeared to show some promising results from the anti-inflammatory drug tocilizumab – trade name Actemra, manufactured by Roche –but it is still too early to draw any firm conclusions.9 Multiple trials are ongoing involving several different anti-inflammatory medicines.
What are the challenges to manufacturing and distributing a vaccine or treatment on a global scale?
Setting up the mass manufacturing of a new drug is a process that typically takes several years. Facilities are complex and must adhere to the highest standards. Furthermore, processes for making molecules often need to be improved and adapted to move from the scale needed to produce enough for a small clinical trial to a large scale capable of producing millions of doses. This all takes time. We may see companies with spare manufacturing capacity collaborating with companies developing treatments or vaccines against the virus.
There have been questions over whether the virus could mutate, reducing the effectiveness of a treatment or vaccine. Currently we do not know enough about the virus to be sure if this is likely to be an issue. The leading vaccine candidate directs the immune system to target the spike protein found on the surface of the virus, so if the virus were to mutate in a way that changed the structure of the spike protein, this could impair the effectiveness of a vaccine targeting this structure. However, Moderna has worked successfully on a vaccine against the Middle East respiratory syndrome coronavirus MERS-CoV, that was first identified in 2012, by targeting spike protein. They have identified some similarities between the two coronaviruses’ proteins, which could help in the development of a vaccine.
Overall, we are seeing promising progress around the development of potential vaccines and antiviral drugs, though this will take time. However, in the short term, any indication that a vaccine or treatment is close will shape market sentiment and should help restore confidence that an end to the pandemic is in sight.
- https://clinicaltrials.gov/ct2/show/NCT04257656; https://clinicaltrials.gov/ct2/show/NCT04252664)