SARS-CoV-2 and it’s variants
The genetic material of SARS-CoV-2, the virus responsible for COVID-19, is made up of RNA. RNA viruses tend to mutate more readily than DNA viruses and so will produce more variants as their replication methods are error prone. The majority of these mutations are deleterious to the virus, meaning that those particles containing the mutation are either unable to spread, or will not spread as effectively as its parental virus. Advantageous mutations help the virus enter the host more efficiently or allow it to better evade the host’s immune response. These mutations give the virus a selective advantage, allowing it to spread rapidly in the population. Whilst they can occur anywhere in the virus, the mutations of most concern from a healthcare perspective, are those in the Spike proteins, which protrude from the surface of the virus.
The Spike protein
Spike proteins are responsible for the virus gaining entry into the host cell. Subtle changes arising from mutations can alter these proteins just enough to allow them to bind more readily to host-cell receptors, resulting in more efficient entry. The Spike is also the main protein that the body produces antibodies against, as well as the being the target of current vaccines. Mutations in the Spike have the potential to escape the antibodies produced after vaccination or by someone who has been previously infected, allowing reinfection.
SARS-CoV-2 belongs to a group of viruses called enveloped viruses. The genetic material of these viruses is coated in a protein capsid, which is further surrounded by a lipid envelope, with the Spike proteins anchored into it. Whilst enveloped viruses can be stable on surfaces for prolonged periods of time, they are relatively fragile and are susceptible to chemical inactivation through the disruption of the lipid envelope. Such disruption prevents the virus from infecting a host.
The efficacy of hand sanitisers and surface disinfectants
Disinfectants and hand sanitisers contain a range of active substances, each with a differing mechanism of action. In the disinfection against enveloped viruses, the ultimate goal is to break open the lipid membrane. Mutations in proteins such as the Spike result in relatively subtle alterations in the overall structure of the protein and do not influence the lipid membrane. This means that the mechanism of inactivation when disinfecting is effective regardless of the mutations in the virus. Products with proven efficacy against one variant will be equally effective against all of them. Using an effective surface disinfectant with long lasting action will further aid in the reduction of viral spread.