Get the latest on coronavirus. Sign up to the Daily Brief for news, explainers, how-tos, opinion and more.

The director of the World Health Organization warned Monday that there may never be a “silver bullet” for defeating Covid-19, even as pressure mounts from the White House to create a vaccine well before the end of this year.

“A number of vaccines are now in phase 3 clinical trials and we all hope to have a number of effective vaccines that can help prevent people from infection,” WHO Director-General Tedros Adhanom Ghebreyesus said at a media briefing. “However, there’s no silver bullet at the moment and there might never be.”

Tedros instead stressed the importance of exercising “the basics of public health and sieges control” to stop outbreaks from occurring.

“Testing, isolating and treating patients, and tracing and quarantining their contacts. Do it all,” he urged.

There are currently six coronavirus vaccine candidates in late-stage testing or close to it.

Dr. Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases and a White House coronavirus task force member, said last week that he’s “cautiously optimistic that we will have a vaccine by the end of this year and as we go into 2021.”

But Fauci has also said he doesn’t believe the virus will ever be eliminated.

“I think with a combination of good public health measures, a degree of global herd immunity and a good vaccine, which I do hope and feel cautiously optimistic that we will get, I think when we put all three of those together, we will get control of this, whether it’s this year or next year. I’m not certain,” he told the TB Alliance in an interview last month. “I don’t really see us eradicating it.” 

President Donald Trump, in contrast, has repeatedly insisted that the virus will one day “disappear” and has called Fauci an “alarmist.” At a news conference last month, Trump said he expects there will be a vaccine “long before the end of the year.”