In 2000, a new pill called pleconaril was developed to treat the common cold. Initial clinical trials looked promising, with the pill helping many patients. But just a few days into treatment, researchers discovered the virus had already mutated in some patients, making it almost completely resistant to the drug’s effects. This rapid mutation enabled the virus to evade the pill that had taken years of research to develop.
Viruses are constantly mutating as part of their replication process. Normally our immune systems can handle these mutations. But for people with compromised immune systems, even a minor infection can become life-threatening.
On average, healthy adults will catch more than 150 colds in their lifetime. And despite causing similar symptoms, each incident can be caused by different viruses. At least 8 families of viruses are known to cause the common cold, each with multiple species and subtypes.
How Can So Many Different Viruses Cause the Same Illness?
Viruses invade our bodies in limited ways, so our immune systems have evolved frontline defenses that produce many cold symptoms. Your runny nose is from mucus trapping viruses. Fevers slow viral replication. Inflammation brings white blood cells to help eliminate the infection.
So even with various viruses causing colds, a cure may be possible by targeting the most prevalent culprits. One viral family – rhinovirus – accounts for 30-50% of colds. Stopping rhinovirus could go a long way towards preventing the common cold. But after decades of work, vaccines and drugs have yet to provide a cure.
Challenges in Developing a Rhinovirus Vaccine
In 1957, Dr. William Price vaccinated children with inactivated rhinovirus, resulting in fewer colds compared to unvaccinated kids – initially. But later trials showed no protection at all.
We now know there are over 169 subtypes of rhinovirus. Price’s vaccine likely only covered one or a few subtypes. Some vaccines elicit broad immunity, like the mRNA COVID vaccines. But a universally protective rhinovirus vaccine remains elusive.
Why Is Developing a Rhinovirus Vaccine So Difficult?
- There are over 169 subtypes that can cause infection
- Subtypes have different surface proteins, making broad immunity difficult to achieve
- Frequent mutations lead to emergence of new strains not covered by previous vaccines
Research continues, but a single rhinovirus vaccine that protects against all subtypes has not yet been developed.
Challenges in Developing Anti-Viral Drugs
Another approach is anti-viral drugs to treat existing infections or provide short-term protection. However, viruses depend on human cells to replicate, so it’s challenging to harm the virus without damaging healthy cells.
And even effective drugs can quickly become obsolete as viruses mutate. Some viruses, like influenza, mutate so rapidly that new flu shots are needed every year. Other viruses, like smallpox, mutate slowly and were eradicated with vaccines.
Case Study: HIV vs. Smallpox
- HIV mutates rapidly, eluding decades of vaccine research. But anti-viral drug cocktails effectively treat HIV by attacking it from multiple angles.
- Smallpox mutated slowly and was eradicated by 1980 thanks to its exclusive human host, relatively low mutation rate, and an effective vaccine.
For now, rhinovirus continues to mutate quickly and evade drug treatments or vaccines that provide long-lasting, broad protection. Are there any new approaches that could finally provide a cure?
New Scientific Breakthroughs Like CRISPR May Lead to a Cure
In recent decades, revolutionary technologies like mRNA vaccines and CRISPR gene editing have been developed. These new tools could enable breakthroughs against stubborn viruses like rhinovirus.
In particular, CRISPR shows promise as it originally evolved in bacteria to fight viral infections. Early in the COVID pandemic, researchers used a CRISPR system in lung cells to successfully degrade coronavirus and influenza. The technology was nicknamed PAC-MAN, highlighting its viral munching abilities.
How Could New Technologies Lead to a Cure?
- mRNA vaccines – Enable rapid development of vaccines against mutating strains
- CRISPR – Can be programmed to directly destroy viral genetic material
- Virus monitoring – Better tracking of viral spread and mutations in real time
- Computer modeling – Simulate virus behavior and predict future mutations
- Nanotechnology – Develop microparticles that trap viruses before cell entry
After decades of frustration, emerging innovations like these give hope that the common cold may someday meet its match. While challenges remain, the outlook is brighter than ever for outsmarting rhinovirus and finally curing the ubiquitous cold.
Conclusion: A Cure is Difficult But Possible
For now, rhinovirus continues causing seasonal misery with its rapid mutations and many distinct strains. Neither vaccines nor drugs have been able to provide long-lasting protection against the plethora of subtypes. But innovative technologies like CRISPR and better understanding of viral behavior offer hope for the future.
Developing a cure for the common cold faces substantial scientific obstacles. But the COVID pandemic demonstrated that rapid innovation is possible when we combine brilliant minds, new technologies, and ample resources. While it may take years or decades more work, the goal of permanently defeating the common cold remains tantalizingly within our grasp.