Variante do coronavírus com elevada mutação
November 26, 2021 - Uma nova variante do coronavírus detetada no sul da África tem 50 mutações, incluindo 30 alterações na proteína espícula que infeta as células hospedeiras e é o alvo da maior parte das vacinas contra a Covid.
With around 100 cases confirmed in South Africa, some scientists attribute the variant to the country’s rapid rise in cases. Covid infections surged from 868 on Tuesday (November 23) to 2,465 yesterday.
Hong Kong has reported two cases among travellers from southern Africa. Because the two patients were in separate rooms, there is concern this variant is airborne.
The United Kingdom, Singapore, and Israel have announced temporary bans on flights from South Africa and Botswana, Eswatini, Lesotho, Mozambique, Namibia, and Zimbabwe.
In a media briefing, Professor Tulio de Oliveira, Director of South Africa’s Centre for Epidemic Response and Innovation, said there were 50 mutations overall. And more than 30 on the spike protein, which is the target of most existing vaccines.
In addition, the tip of the spike -- the receptor-binding domain (RBD), which binds with human host cells -- has ten mutations. The Delta variant that swept the world has just two RBD mutations.
The RBD is a vital part of a virus located on its spike. It allows it to dock to body receptors to gain entry into cells and lead to infection.
The high number of mutations could make it harder for antibodies to recognise the virus, make it more resistant to vaccines, increase transmissibility and lead to more severe symptoms.