The South African variant is more resistant to the Pfizer vaccine than other coronavirus strains, according to new research conducted by Ben-Gurion University of the Negev scientists. In addition, its infectivity appears to be similar to the British variant and therefore higher than that of the original strain of the disease.
“We saw a seven-fold decrease in the Pfizer vaccine’s ability to inhibit infection by the South African variant of the virus,” said Prof. Ran Taube of BGU’s Shraga Segal Department of Microbiology, Immunology and Genetics in the Faculty of Health Sciences.
The study did not take into consideration clinical data, but rather, it analyzed blood taken from inoculated patients, he told The Jerusalem Post.
“We incubated blood taken from vaccinated individuals, and we measured the ability of the antibodies to inhibit infection,” Taube said. “The vaccine still worked against the South African [variant], but in a less-efficient way.”
The coronavirus vaccine’s efficacy is generally described as employing several indicators. Besides preventing infection, the ability to prevent severe symptoms and death is also considered, and for many experts, the latter two are even more important than the first.
The Pfizer vaccine has so far demonstrated to be some 95% or more effective in all the three categories, at least against the original strain of the virus and the British variant. Other coronavirus vaccines approved by health authorities in Western countries, while sometimes showing a lower level of protection against infection, have still demonstrated a high capability to prevent more serious forms of the disease.
Because of the nature of the study, researchers did not consider the clinical significance of the findings or whether a lower efficacy in preventing infections also translates into a lower capability of preventing severe symptoms or death, Taube said.
“We did see that the ability of the South African variant to spread is comparable to that of the British one,” he said.
The study was led by Taube and co-authored by Alona Kuzmina, Yara Khalaila, Olga Voloshin, Ayelet Keren-Naus, Liora Bohehm, Yael Raviv, Yonat Shemer-Avni and Elli Rosenberg. It was published in the journal Cell Host & Microbe on Sunday.
The researchers also found that antibodies produced after two shots of the vaccine were at higher levels than those in people who had recovered from the disease and did not get inoculated.
The group is now focusing on mapping other variants.
“The idea is to try to identify which unique mutation in the spike of the virus is responsible for each of the findings that we saw, which causes higher infectivity, which causes higher resistance to vaccination and so on,” Taube said. “There are other variants that are incubating and are emerging, and we hope to characterize each one of them in a very systematic way.”