The problem is persistent: a fully vaccinated public figure catches Covid-19, and social media sites are soon flooded with claims that this proves the shots do not work.

From White House Press Secretary Jen Psaki, US Supreme Court Justice Brett Kavanaugh, and American comedian Chris Rock testing positive to former secretary of state Colin Powell dying of Covid-19 complications, prominent cases have triggered a deluge of inaccurate information online.

So-called breakthrough cases are expected and do not mean the vaccines are ineffective, US health authorities say.

But claims that the shots are failing can erode trust and slow uptake efforts, which remain crucial as younger children become eligible for the shots, AFP reports.