However, Fauci added that there is “growing optimism” that researchers will discover one or more safe and effective vaccines by the end of the year and the beginning of 2021 and that the United States will have enough doses of vaccine by April, Reuters reports.

US President Donald Trump has insisted that the United States could have a safe and effective vaccine by the end of October and that it will have enough doses to vaccinate all Americans by April. The president’s comments contradicted the claims of health officials and raised concerns that the vaccine approval process will be influenced by politics and not science.

On Wednesday, Fauci set a similar deadline for when vaccine doses will be available to all Americans, saying vaccine doses will be distributed in the coming months and that the United States should have 700 million doses by April.

“There will probably be 50 million doses available in November. By December, maybe more than 100 million. Then we will enter January and February. By April, we will reach a total of about 700 million, “Fauci said in a hearing in a Senate subcommittee.

In remarks prepared for the hearing, Fauci referred to vaccines developed by Moderna, Pfizer, AstraZeneca and Johnson & Johnson, which received federal support through Operation Warp Speed ​​and began final clinical trials.

Fauci said a fifth vaccine, developed by Novovax, will enter a final clinical trial in October.

The director of the Center for Disease Control and Prevention, Dr. Robert Redfield, said in a Senate hearing last week that vaccinations are expected to begin in November or December and will last “six to nine months” for the entire American population. to be vaccinated. The United States will be able to resume normal life in the third quarter of next year, he said.