Being a variant of concern means that these variants can have an impact on immunity, severity, and infectiousness of the virus. For example, researchers discovered that the Alpha and Delta variants are more deadly. These variants are high on the priority list of variants that need to be monitored and observed. Vaccine manufacturers are also studying these variants to find out how to improve their vaccines against these mutations.
Some variants of concern might be also more resistant to immunity, which is why scientists are studying them in order to figure out how to fight the virus.
With regard to the variants of interest, these variants could have the potential to eventually become variants of concern. However, more evidence will be needed to see how big of an impact these variants could have if more people are infected.
Scientists have designated some variants as variants under monitoring. These variants could have some of the traits of variants of concern, but there is not yet enough evidence to show this, or they haven’t been fully studied yet.