The virus that causes the COVID-19 disease, SARS-Cov-2, mutates, as do other viruses.
What is a strain
The strain from German literally translates as "trunk, lineage". A strain is a population of organisms of the same species that have a unique, characteristic DNA or RNA sequence.
A virus strain is a genetically distinct mutation (one or more) from the main virus. The difference may be small, but any difference and a new RNA sequence is a new strain.
There is no generally accepted type of name for the strains, but most often they consist of letters and numbers, for example, the British strain of the coronavirus is called VOC-202 012/01.
In nature, there are several thousand strains of the SARS-CoV-2 virus, but they are combined into seven clades—a group of organisms with a common ancestor. In total, seven clades were identified—O, S, L, V, G, GH, and GR. In December 2019, L was found in Wuhan.
British strain of coronavirus
Name: VOC-202 012/01
It appeared in September 2020 in England. According to the WHO, the British strain of coronavirus is spreading faster than usual. This strain is believed to be more deadly. British scientists have stated that the risk of mortality from this strain is 30% higher. However, the studies published in The Lancet Infectouse Diseases and The Lancet Public Health did not confirm the fears about a more severe course of the British strain in patients. Both studies confirmed the higher infectivity of the British strain, but found no evidence of a link between the variety of strains and more severe illness or death.
It spreads in the same way as the main coronavirus, so the control measures will be the same. The total number of countries where the British strain was recorded has reached 139.
The main symptoms of the British strain of coronavirus are: cough, severe fatigue, sore throat and muscle pain. Anosmia and ageusia are less common.
The British strain is already spreading across Ukraine.
South African strain of coronavirus
Name: V2 or B. 1.351
It was first discovered in Nelson Mandela Bay County in the Eastern Cape of South Africa in December 2020. According to the Times of Israel study, this strain is more resistant to the Pfizer-BioNTech vaccine. The study results have shown that the South African strain, in comparison with the original and British strains, is able to "break through the protection of the vaccine." But so far the sample is not enough to assess its real properties. The South African strain contains several mutations that allow it to more easily attach to human cells.
The strain is more likely to spread in young people without co-existing diseases, but it often causes diseases.
The most common symptoms of the South African strain of coronavirus are body pains, joint or throat pain, diarrhea, conjunctivitis, headache, fever, cough, loss or change in smelling and taste.
In early April 2021, a South African strain was found in two regions of Ukraine.
Brazilian strain of coronavirus
The Brazilian strain of coronavirus was identified in the Brazilian city of Manaus in January. This strain has mutations in the spike protein that makes it easier for the virus to enter the human body. Another mutation helps the virus elude the immune response. This can lead to reinfection with the coronavirus. Deepti Gurdasani, senior lecturer and epidemiologist at Queen Mary University of London, told Al-Jazeera during the interview about the threat of the Brazilian coronavirus strain rapid spread.
The Brazilian strain is able to largely overcome the immunity developed in people who have recovered, the Financial Times reported, citing a joint study conducted by the universities of Oxford, São Paulo, and Imperial College London.
The Pfizer/BioNTech vaccine has been able to neutralize the Brazilian strain in the laboratory, according to a study published in the New England Journal of Medicine.
Indian strain of coronavirus
It was first recorded in India in December 2020. According to the WHO European Bureau, the "Indian" strain has already been recorded in more than 10 countries in Europe, the USA, Australia, and Singapore.
According to preliminary studies, a mutation in this strain can affect the efficacy of some monoclonal antibody treatments. The other one neutralizes antibodies and that will not save a person from re-infection.
Also, the new strain has a higher ability to cause disease or death.
Less common strains of coronavirus
10% of patients in Denmark were infected with the Danish strain. However, the hospitalization rate is lower than in the case with the original coronavirus strain.
In December 2020, a new strain was recorded in Nigeria. It was identified against the background of an increase in the number of infections, but there is no evidence of its greater infectiousness yet.
In the United States, a strain of coronavirus could have appeared. This was suggested after a surge in new cases of the disease in the fall-winter of 2020-2021.
Malaysian scientists have also recorded a new strain of coronavirus.
Scientists continue to study these strains and do not exclude the emergence of new ones.