South African Covid-19 variant shows resistance to vaccines, study says

Written by: Dr. Ali Khatau

Posted at: 2021-04-07 12:02:15

The Covid-19 variant B.1.351, which originated in South Africa, shows increased resistance to both post-infection antibodies and two available vaccines, according to research published in a correspondence letter in the New England Journal of Medicine on Tuesday.  Variant B.1.351 showed resistance to “convalescent serum,” generated with samples taken from people previously infected with Covid-19, and to “vaccine serum,” testing both the Sinopharm and Sinovac vaccines, which use inactivated forms of the virus.   B.1.351 showed increased resistance to the convalescent serum by a factor of two, and resistance to the vaccine serum by a factor of 2.5 to 3.3 when compared to an engineered version of the “wild type” of the virus, or the Wuhan-1 reference strain. Nearly a third of the convalescent serum samples showed a total loss of neutralization against B.1.351. Two-thirds of the samples of the Sinopharm vaccines had either a partial or complete loss of neutralization against the variant. Most of the CoronaVac samples showed some amount of lost neutralization against B.1.351. The variant B.1.1.7, which originated in the United Kingdom, showed little resistance to either the vaccine serum or convalescent serum. Both the Sinopharm and CoronaVac vaccines showed a lowered antibody response when compared to convalescent serum. 

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