The first problem, Fauci explained to CNN, is that the vaccine might only be 70 to 75 percent effective. The most effective vaccine up to this point is the measles vaccine, which is 97 to 98 percent effective, but Fauci does not believe we’ll get there with coronavirus, which is why he’s prepared to “settle” for efficacy in the 70 to 75 percent range. The second problem is that not everyone is going to be willing to get the vaccine. A May poll from the Associated Press-NORC Center for Public Affairs Research had 20 percent of respondents saying they would refuse the vaccine, with an additional 31 percent saying they were uncertain. In another May poll from CNN, one-third of respondents said they would not get a COVID-19 vaccine, even if it were inexpensive and readily available. As Fauci notes, these problems together mean that the vaccine would most likely not be enough for the U.S. to reach herd immunity, which is when enough of the population is immune to a virus—whether from a vaccine or prior infection—to prevent the virus from spreading further. In the case of most viruses, 7o to 90 percent of the population needs to be immune to achieve herd immunity.ae0fcc31ae342fd3a1346ebb1f342fcb With a vaccine that could be as low as 70 percent effective, and a substantial portion of the population unwilling to get vaccinated, hitting that target is tough to imagine. “It’s not going to be easy” convincing people to get vaccinated, Fauci told CNN. “Anyone [who] thinks it will be easy is not facing reality. It’s going to be very difficult.” RELATED: For more up-to-date information, sign up for our daily newsletter. There are other problems to consider when it comes to a coronavirus vaccine. It’s unclear how long immunity would last, so people might need multiple shots to maintain that immunity—and that could take more convincing. It would also present even bigger challenges in terms of vaccine production, and some experts have already sounded the alarm about supply chain problems down the line. There were hopes that contact tracing could greatly slow the spread of coronavirus before the development of a vaccine, but as Fauci told CNN, those efforts are not proving terribly effective. That matches what he told CNBC on June 26, when he said contact tracing is “not going well.” For now, the best advice remains wearing masks and social distancing as the country tries to get the outbreak under control. And to learn more about a potential vaccine, check out these 7 Questions About the Coronavirus Vaccine, Answered by Doctors.

Fauci Says a COVID Vaccine Won t Be Enough to Achieve Herd Immunity - 47