By Nikhila Natarajan

New York, Nov 9 (IANS): "Extraordinary" is how America's top infectious diseases expert Anthony Fauci is reacting to the news of Pfizer's vaccine candidate achieving 90 per cent effectiveness.

"Not very many people expected it would be as high as that," Fauci has been quoted as saying by US news wires.

Fauci called the development "extraordinary".

Fauci has held to his "cautious optimism" for months now, that a vaccine will be ready to go by end of the year.

After nine months of utter chaos, politics and science are both moving at phenomenal speed the weekend after election results.

US President Donald Trump seized on the news, tweeting: "STOCK MARKET UP BIG, VACCINE COMING SOON. REPORT 90% EFFECTIVE. SUCH GREAT NEWS!"

Trump's son Donald Trump Jr leaned into the "timing" of the news. "The timing of this is pretty amazing. Nothing nefarious about the timing of this at all right?"

US markets boomed, the Pfizer stock exploded and vaccine-related pharma stocks are up all around.

Pfizer has cautioned that the protection offered by the vaccine might change by the time the study ends.

"It's a great day for science, great day for humanity!", a beaming Pfizer CEO Albert Bourla told reporters.

President-elect Joe Biden also referred to the news in a short briefing on Monday but implored Americans to "please wear a mask, despite the news today."