PFIZER Inc and BioNTech's COVID-19 vaccine appeared to lose only a small bit of effectiveness against an engineered virus with three key mutations from the new coronavirus variant found in South Africa, according to a laboratory study conducted by the U.S. drugmaker. The study by Pfizer and scientists from the University of Texas Medical Branch (UTMB), which has not yet been peer-reviewed, showed a less than two-fold reduction in antibody titer levels, indicating the vaccine would likely be effective in neutralizing a virus with the so-called E484K and N501Y mutations found in the South African variant. The study was conducted…