It’s been two and a half years since the novel coronavirus, SARS-CoV-2, first appeared in humans. During that time, it has mutated, creating variants and subvariants at a rate that has surprised scientists. And it shows no signs of slowing down.

The main concern with the virus’ ability to change is that even though it’s already highly contagious, it’ll become even more so. According to the Centers for Disease Control and Prevention (CDC), preliminary research indicates that the latest subvariant of omicron, BA.2.12.1, is about 25 percent more transmissible than the BA.2 subvariant that is currently the present dominant nationally.

The original omicron variant was more transmissible than delta, and delta was more transmissible than alpha, which was more transmissible than earlier variants. While most mutations are not beneficial to the virus, when one does offer some advantage, the process of natural selection will favor it. So, we can expect to see the emergence of new variants and subvariants. For instance, scientists in South Africa have identified BA.4 and BA.5, mutations that were seen in earlier variants and are associated with the ability to evade the immune system.

The bottom line?

It’s going to be impossible to prevent the spread of covid.

In a recent briefing, President Biden’s new Covid-19 Coordinator, Ashish Jha, said that the goal isn’t to isn’t “to ensure that no one gets Covid in America.” He points to what has become apparent in the past several months. There’s no such thing as total protection against infection with Covid, regardless of how many vaccines a person has had due to the speed at which the virus is mutating.

The vaccines were developed based on the genomic sequence of the original viral strain that appeared late in 2019 in Wuhan, China. They work by mimicking the spike protein of that particular viral strain and triggering an immune response. This allows the body’s immune system to recognize and fight the actual virus. However, as variants have emerged, they can dodge the neutralizing antibodies that the immune system has developed.

Instead, the primary function of vaccines is to decrease the risk of severe illness. Along with the wider use of therapeutics, like the antiviral Paxlovid, the goal is to reduce the number of people who need to be hospitalized and could die from the disease. A worst-case scenario would be the emergence of a variant that renders current vaccines largely ineffective.

The concern from infectious-disease experts is that while variants so far have been highly transmissible, they’ve been less lethal than previous variants. With future variants, we might not be so lucky.