Filenews 16 March 2021
According to the relevant publication in Nature, the study predictions are now confirmed with the first recorded results of the Novavax vaccine. The company that developed this vaccine said on 28 January that it was almost 90% effective in testing for the British mutation, but only 49.4% for South African.
"Our study and data from the new clinical trial show that the virus is evolving in a direction that goes beyond existing vaccines and therapies aimed at spike protein," says lead author and director of the AIDS Research Centre Aaron Diamond, Dr . David Ho adds:
"If the uncontrolled spread of the virus continues and more dangerous mutations accumulate, then we will be doomed to constantly pursue the evolution of SARS-CoV-2, as we have been doing for a long time with the influenza virus. Such estimates require stopping the transmission of the virus as quickly as possible, doubling the measures to contain the virus and anticipating the development of vaccines.
As scientists say, after vaccination, the immune system responds and produces antibodies that can neutralize the virus. Dr. Ho and his team, therefore, found that antibodies in the blood samples of people vaccinated with the Moderna or Pfizer formulation were less effective in neutralizing both the British strain that emerged in September and the South African that occurred in late 2020. Against the former the neutralization decreased almost twice, while against the second by 6.5-8.5 times.
"The nearly double loss of neutralising action against the British strain is unlikely to have adverse effects due to the safety offered by the rest of the antibody activity, as shown by the results of the Novavax vaccine where the formulation was shown to be 85.6% effective against the British mutation," points out Dr. Ho.
Data on the loss of neutralising activity against the South African mutation, however, are more worrying.
"The drop in neutralising activity against the South African mutation is remarkable and we now see, based on Novavax's results, that it causes a decrease in protective efficacy," explains the expert.
The new study did not examine the new strain of the virus found in Brazil, but given similar spike mutations between Brazilian and South African strains, scientists argue that the Brazilian mutation should behave similar to the South African one.
"We need to stop copying the virus and that means faster vaccine development and obedience to virus containment measures, such as mask use and social distance. Stopping the spread of the virus will stop the development of further mutations," points out Dr. Ho.
Effects of treatments with monoclonal antibodies
The study also found that some monoclonal antibodies used to treat patients with COVID-19 may not work against the South African mutation.
Specifically, it measured the neutralizing activity of 18 different monoclonative antibodies, including those in two vaccines approved for use in the US.
Compared to the British mutation most antibodies were still strong, although the neutralizing activity of two developing antibodies was moderately reduced.
Compared to the South African mutation, however, the neutralizing activity of four antibodies had been completely or significantly eliminated. These included bamlanibimab, a recombinant, neutralizing human IgG1 monoclonate antibody (mAb) directed against the SARS-CoV-2 spike protein. Bamlanibib was completely inactive against the South African strain and one of two antibodies to an approved cocktail of antibodies that was 58 times less effective at neutralizing the South African strain than the original virus – the second antibody to the cocktail maintained its neutralizing ability, as did the entire cocktail.
"Decisions on the use of these therapies will depend strictly on the local prevalence of Brazilian and South African strains, underlining the importance of gene monitoring of the virus and the preventive development of next-generation antibody therapies," notes Dr. Ho.
Effects of re-infection
Based on plasma use of COVID-19 patients infected earlier in the pandemic, strain B.1.351 from South Africa has the potential to cause re-infection.
In particular, serum from patients who had recovered from COVID-19 in the first time of the pandemic had 11 times less neutralising activity against the South African strain and four times less than the British one.
"Our concern here is that re-infection is much more likely if a human is confronted with these mutations, particularly that of South Africa," the scientists conclude.
Source: protothema. gr
