Covid-19 vaccine. "We're gonna get the booster shots," Biden was quoted as saying by news agency Reuters. This comes after the US health officials announced on Wednesday booster shots of the Pfizer and Moderna Covid-19 vaccines are set to become available for all adults in America beginning next month. "We know that even highly effective vaccines become less effective over time," Dr Vivek Murthy, the surgeon general, said at a White House briefing. "It is now our clinical judgment that the time to lay out a plan for Covid (vaccine) boosters is now." It's now "very clear" that immunity starts to fall after the initial two doses, and with the dominance of the delta variant, "we are starting to see evidence of reduced protection against