If nothing else, this pandemic provided a much-needed fillip to the medical industry. It led to a breakthrough in the development of vaccines in general. According to the past projections by Moderna (one of the first companies to enter the vaccine race), the current technology being used to produce Covid vaccines was still 3-4 years away. And now, just a year into the pandemic, mRNA vaccines have forever changed the industry’s outlook; allowing production of Covid vaccines for testing within weeks, which earlier took years. Although scientists had already been working on developing this, it became the need of the hour when the pandemic hit; Covid-19 motivated them to fast-forward with the technology. However, there are still a lot of uncertainties in play. With the virus mutating itself, it is important to keep track and create mutations of the Covid vaccine itself.
The new messenger-RNA technology (mRNA) chemically synthesizes a strand of the ribonucleic acid (RNA) of SARS-Cov-2. It encloses the strand inside a lipid shell, to prevent degradation. Once the vaccine is injected, the shell attaches to a human cell. The RNA strand instructs the human cell to produce a specific protein that helps the immune system to recognize the actual protein used by the virus. A vaccinated person’s body, if infected, will recognize the actual ‘spike’ protein, and initiate the defense response. Unlike traditional vaccines, these contain only the protein-creating RNA, and not the actual virus. The traditional vaccines use small doses of live or inactive virus, which unfortunately, are less effective. According to the Centers for Disease Control and Prevention, influenza vaccines reduce the risk of catching the seasonal flu only by 40-60 percent. The Covid vaccines, although not perfect, have an efficacy rate of more than 90 percent!
Where it Diverges from Traditional vaccines:
One of the biggest advantages of the development of mRNA vaccines is the speed at which one can produce vaccines. This is because laboratories simply need the genetic sequencing to design mRNA particles, following a process similar to 3D printing. They do not need to grow cell cultures through biological processes as was the case until a year ago. This cuts down the time of obtaining FDA approvals, making it easier to develop mutations of the Covid vaccine. This is not to say that the vaccines are flawless. The presence of the RNA component necessitates storage in sub-freezing conditions, which poses a costly distribution challenge. Moreover, once the messenger RNA teaches the cell the produce the protein, it degrades. This means that it requires two doses for the vaccine to become effective, and it is possible for a person to become infected by Covid in between the two stages.
Mutating Virus v/s Mutating Vaccine:
The fact that the virus is mutating, does nothing to help with the complications. Scientists have found new coronavirus strains in South Africa, Brazil, UK and the US. The existing vaccines may not be effective in fighting against all these new variants. Richard Hatchett, CEO of the Coalition for Epidemic Preparedness Innovations, said, “We cannot be complacent that we’ve got the vaccines we need […] We’re in a race with the virus and we’ve got to get ahead of it.” There are also talks of vaccines themselves driving mutations of the virus. The main concern is the possibility of infection in the period between the two doses. This might serve as a breeding ground for the virus to acquire new mutations. There are also questions around the extent to which the mutations of the Covid vaccine prevent infections. And even then, the vaccinated person can act as a carrier.
The Road Ahead:
Scientists are, thus, facing a trade-off. While the vaccines have an efficacy rate of more than 90 percent, it is still unclear whether this is achieved after the first dose or the second. However, vaccines do reduce the risk of illness and disease. So, it makes sense to get the maximum people vaccinated as quickly as possible. One suggestion has been to use the scarce vaccines to give the first doses, to achieve partial immunity in maximum people. This, then runs the risk of acting as a breeding ground for the virus. Andrew Read, an evolutionary microbiologist, said, “While extending the time between the two doses does run the risk of promoting evolution, at the moment, that seems like a second-order issue compared to just reducing the transmission through the population as a whole.”
Other than this, studies have shown that people who have been infected with the virus, produce T-cells that target different virus proteins. These T-cells, fortunately, continue to be effective against a new strain as well. This approach is under review to develop broader resistance to coronavirus despite the genetic changes. Researchers are also looking into combining the mutations of the Covid vaccine into an ‘all-in-one’ vaccine; one that can target and neutralize multiple forms of this virus. The British government announced its collaboration with CureVac NV to develop shots; combining the use of artificial intelligence to predict future mutations, with the mRNA technology. Scientists have also started work on developing a vaccine that induces antibodies in the nose and throat, the main route for infection.
For now, the presence of a number of mutations of the Covid vaccine has resulted in a heterogeneously vaccinated population. This is believed to help slow down the spread of the mutants, as the virus will have to face different defenses in each host’s body. Needless to say, new strains have pushed the finish line for herd immunity a bit further. Thus, the best bet to slow the spread of the virus is to keep wearing masks, washing hands and practicing social distancing.
- Secret ingredients behind the breakthrough Covid vaccines, Financial Times, November 20, 2020
- Covid-19 vaccines could add to fuel to Evolution of Coronavirus Mutations, NPR, February 10, 2021
- Rise of variants sparks push for all-in-one Covid-19 vaccines, The Straits Times, February 13, 2021
- How will vaccines fare vs Covid strains, Times Standard, February 21, 2021