COVID variants could get around the human immune response. “Immune escape” could mean more people who have had COVID-19 could get reinfection and current vaccines may need an update.
UK Variant B.1.1.7 is spreading faster in the UK and other countries but a South Africa 501Y.V2 variant is also worrying experts. The South Africa mutations (E484K and K417N) change its surface protein, spike, and have been shown in the lab to reduce how well monoclonal antibodies combat the virus. A preprint paper by , Jesse Bloom, an evolutionary biologist at the Fred Hutchinson Cancer Research Center, showed that E484K reduced the potency of convalescent sera from some donors 10-fold. This does not mean a people’s immunity to the new strain drops 10-fold but immunity is impacted.
501Y.V2 virus contains nine spike mutations. It
rapidly emerged in South Africa during the second half of 2020, is largely resistant to neutralizing antibodies from people who already had other versions of COVID. New variants such as 501Y.V2 pose a significant re-infection risk.
The impact on the course of the pandemic is unclear. In Manaus, Brazil (2 million people), P.1 might have nothing to do with the new surge in infections. People’s immunity might just be weakening. It could be a combination of factors (weakening immunity and new mutated strains).
London School of Hygiene & Tropical Medicine calculated that South Africa’s 501Y.V2 variant could be 50% more transmissible but no better at evading immunity, or just as transmissible as previous variants but able to evade immunity in one in five people previously infected.
Changes in the efficacy of vaccines and monoclonal antibody therapies targeting SARS-CoV-2 spike need to be closely monitored. Selection pressure from the widespread use of these interventions increases the potential for virus escape. A vaccine or antibody therapy that worked before could stop working if viruses mutate and matches the antibody CDR. This may also lead to Antibody Disease Enhancement (ADE).
Close attention to viral transfer from humans to farm animals and pets will be needed to prevent build-up of a viral reservoir for future zoonotic transfer.
If COVID mutates enough then the world could be looking at 2-3 more years of pandemic. Hygiene protocols will have to be maintained and improved. Virus filtering fans, eating outdoors, hand sanitizer usage and mask-wearing will need to be maintained. We likely will eventually need new vaccines that activate a T-cell response against the core of COVID instead of targeting the spike.
Biden has imposed a travel ban from South Africa. Biden on Monday is also reimposing an entry ban on nearly all non-U.S. travelers who have been in Brazil, the United Kingdom, Ireland and 26 countries in Europe that allow travel across open borders.
Los Alamos National Lab – Tracking SARS-CoV-2 Spike mutations
A SARS-CoV-2 variant carrying the Spike protein amino acid change D614G has become the most prevalent form in the global pandemic.
SOURCES- Journal Science, Nature, Biorxiv, Gen Eng News, Los Alamos National Lab, Reuters
Written By Brian Wang, Nextbigfuture.com