Story at a glance
- The number of deaths from coronavirus have surpassed deaths from SARS.
- Viruses can mutate quickly.
- Vaccine development is a multi-stage process that can take at least one year and often much longer.
The coronavirus situation is serious in China. With the number of deaths at 812 as of Feb. 9, surpassing those from SARS (774 deaths), experts are looking for a treatment and a vaccine for the new virus. Several companies claim to be working on antivirals or vaccines for the new Wuhan coronavirus. But what is that process actually like and how long would it take?
Viruses mutate at fast rates
The genetic material for viruses is ribonucleic acid (RNA). RNA exists in a single strand, unlike DNA which is double stranded. Having only a single strand makes it easier for RNA to get cut up and remixed because only one connection needs to be broken. This means viruses can mutate really quickly, which could potentially make any cure or vaccine obsolete over time.
For viruses that are no longer in circulation like smallpox and polio, that’s not a problem. The vaccines for those viruses will work in perpetuity unless the virus gets out and starts to mutate. That could potentially lead to new strains that aren’t covered by the vaccine. Though that is unlikely even for smallpox, which is highly guarded, this has actually started happening with the polio vaccine.
There are two types of polio vaccines: one that is the “dead” virus administered as a shot and one that is a live, “attenuated” or weakened virus that’s given orally. The oral polio vaccine was discontinued in the U.S. but because of lack of supplies it’s still used in many low-income countries. There have been new cases of polio in unvaccinated people from a mutated version of the virus from the live vaccine.
Long time horizon for developing new vaccines
For most viruses, it won’t be worth it to develop a vaccine unless it has great potential to kill a large percentage of people who get infected and it can spread widely in the population. Most won’t be a big deal in the human population, like common cold viruses.
Viruses can also mutate pretty quickly, picking up new genetic material from other viruses. Researchers can try to estimate the mutation rates for different viruses, but these can change, too, evolving and responding to selection.
Even if you don’t consider mutation rates of viruses, vaccine development in general takes a long time, and, in some cases, many years. The shortest time frame that most experts say is about one year. That’s because the vaccine would have to go through six stages, including a three-phase clinical development stage, according to the Centers for Disease Control and Prevention (CDC).
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By the time an effective vaccine is developed and deemed safe for use, the emergency may be over. Or if the urgency fades before a vaccine is developed, work on the vaccine may stall and fall to the wayside, like with the SARS vaccine.
Treatments or “cures” for viral diseases is a different ballgame. Vaccines are only helpful before infection occurs because they prime our immune system to respond to the virus. Cures are meant to treat infected people and typically target the mechanisms for how viruses get into cells in our body.
There are very few antiviral treatments available, although HIV treatments work differently and live in their own realm. There are some prescription antiviral drugs that work best early in flu illness. That’s because they work by interfering with reproduction of the flu virus by preventing it from jumping from one cell to another. These drugs can reduce the time it takes for symptoms to improve, but not all of them work to the same extent, they don’t eliminate risks of more health complications and viruses can become resistant to the drugs.
No money in vaccine development
During nonoutbreak times, there’s very little incentive to work on vaccines for viral diseases other than the flu, and even then it’s mostly medical research centers working on vaccines. That means they have limited resources to put towards research and development compared to the big budgets of pharmaceutical companies. Pharmaceutical companies instead put their resources into drugs that can bring in the big bucks, like painkillers.
Even if vaccine development can be sped up during an epidemic, that doesn’t mean that production capacity is also there to take the vaccine to scale. For example, a research group that is working on a coronavirus vaccine partners with biotech companies, government agencies, and a university. They need to develop new partnerships to be able to produce mass quantities of vaccines.
Once the emergency is over and there aren’t large funds coming from governments reacting to a crisis, there isn’t much money in creating vaccines. Some of the viruses that currently have a vaccine include measles, polio and human papillomavirus (HPV). In these cases, the potential devastation of those diseases getting out of hand outweighs the costs of developing a vaccine.
It’s a marathon, not a sprint
The efforts to find a cure and vaccine for coronavirus may be a race, but it’s a long one. Although people who are suffering and in the middle of the outbreak may be willing to take any risk, it’s not safe to let people take just any vaccine that seems promising. Current human trials are underway in Wuhan, but those drugs are still experimental.
Some experts suggest creating a global fund for vaccine development. It could fund research into Ebola vaccines and now coronavirus. But a few problems still remain, like not enough vaccine manufacturers and the market for it to be financially viable. A few big diseases that still don’t have vaccines are tuberculosis and malaria, even with loads of funding.
Chia-Yi Hou has a PhD in infectious disease ecology. You can follow her on Twitter @chiayi_hou.
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