Pfizer develops booster shot amid fears its COVID-19 vaccine is less effective against highly-infectious variants from Brazil and South Africa

Pfizer develops booster shot amid fears its COVID-19 vaccine is less effective against highly-infectious variants from Brazil and South Africa. Pfizer CEO Albert Bourla said Tuesday his firm will develop booster shots 'every time' a variant makes its shot less effective. Last week, lab tests suggested Pfizer's current shot worked against the spike protein mutation shared by the UK and South African variants It has not announced testing the vaccine against mutation seen in the South African and Brazilian variants that may make them vaccine-resistant Bourla said despite thinking the shot will work against variants, Pfizer is developing booster shots. Moderna said yesterday it is making a South African variant booster shot after finding immunity to the variant from its vaccine may wane faster