The coronavirus presents little variability, approximately seven mutations per sample. Common influenza has a variability rate that is more than double. Currently, there are six strains of coronavirus. The original one is the L strain, that appeared in Wuhan in December Its first mutation -- the S strain -- appeared at the beginning of , while, since mid-January , we have had strains V and G.
This characteristic probably facilitates the spread of the virus. If we look at the coronavirus map, we can see that strains G and GR are the most frequent across Europe and Italy.
According to the available data, GH strain seems close to non-existence in Italy, while it occurs more frequently in France and Germany. Influenza C viruses can cause mild respiratory illnesses but not epidemics, and modern flu vaccines do not protect against them.
Finally, influenza D viruses primarily affect cattle and are not a problem for humans. The strains recommended for vaccination for the flu season in the northern hemisphere are:. However, flu viruses tend to mutate during flu season, which may alter the effectiveness of the current flu vaccine.
Rarely but sometimes, one of those mistakes will be beneficial. It could, for example, make the virus more easy to transmit from person to person by changing its genetics in some way. The U. This could mean that infected people are "actually producing more of the virus or shedding the virus at somewhat higher levels, and that might be what makes it more transmissible," he added. But viruses acquiring mutations isn't "necessarily a bad thing," Jasmine Plummer, Ph. Near the end, the virus might figure out a way A new strain occurs when a virus goes through one or more mutations that change its behavior in some way, but a variant develops when a virus goes through a mutation of any kind, explained Dr.
Patricia Couto, an infectious disease physician at Orlando Health in Florida. According to Lopman, "there are many variants out there," but a few are concerning because they "appear to be spreading more quickly" and could "possibly replace the variants that were previously dominant," he said. The Alpha variant was the dominant variant in the U. This variant is believed to have first emerged in India in October It's since spread to the U. Some variants emerge and disappear while others may emerge and persist.
New variants will continue to emerge. Vaccines are also highly effective against severe illness. Some variants seem to spread more easily and quickly than other variants, which may lead to more cases of COVID An increase in the number of cases will put more strain on healthcare resources, lead to more hospitalizations, and potentially more deaths. These classifications are based on how easily the variant spreads, how severe the symptoms are, how the variant responds to treatments, or how well vaccines protect against the variant.
Severe illness and death: May cause more severe cases than the other variants. Vaccine: Vaccine breakthrough infections are expected, but vaccines are effective at preventing most infections. Infections happen in only a small proportion of people who are fully vaccinated, even with the Delta variant.
Early evidence suggests that fully vaccinated people who become infected with the Delta variant can spread the virus to others.
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