(CNN) Only about half of Americans said they would try to get a Covid-19 vaccine once one is available, according to a new CNN Poll conducted by SSRS, and that percentage appears to have dropped since May.
If a Covid-19 vaccine were widely available at a low cost, 51% of respondents in the survey said they would try to get vaccinated, 45% said they would not try and 4% had no opinion, according to poll findings released on Monday.
Those responses to the poll came from last week, between October 1 and 4.
Health experts have warned that if enough people choose not to get a Covid-19 vaccine, it may keep the US from herd immunity against the coronavirus.
The percentage of respondents in the poll who would try to get vaccinated appears to have fallen when compared with results in CNN polls from previous months. In May, 66% said they would try to get a Covid-19 vaccine, and in August, 56% said they would try. At 51%, the October results showed the smallest share so far in CNN polling to say they would try to get the vaccine.
The percentage of respondents who would not try to get a vaccine appears to have slightly increased compared with the previous months -- it was 33% in May and 40% in August.
Poll responses also appear to varied by demographic.
Sixty percent of those age 65 and older said they would try to get a vaccine. Among those younger than 45, 49% said they would try. In October, 58% of men compared with 45% of women said they would try to get vaccinated; 56% of White people compared with 44% of people of color said they would try.
Responses varied by politics, too -- 42% of people who approve of President Donald Trump compared with 59% of those who disapprove said they would try to get a Covid-19 vaccine.
In May, 51% of Trump supporters said they would try to get a vaccine, in August, it was 38% and in October, it was 41%. In May, 79% of supporters of Democratic nominee Joe Biden said they would seek a vaccine and in August, it was 74%. In October, it shrunk to 60%.
Still, the poll found that 61% of Americans are confident that the ongoing vaccine trials are properly balancing safety and speed, even as Trump has touted the speed at which a vaccine could be made available.
The CNN Poll was conducted by SSRS October 1 through 4 among a random national sample of 1,205 adults reached on landlines or cellphones by a live interviewer. Results for the full sample have a margin of sampling error of plus or minus 3.3 percentage points.
The hesitancy of many people to get a Covid-19 vaccine when it becomes available is an issue that needs to be urgently addressed, National Institutes of Health Director Dr. Francis Collins said in September.
"Those who are vaccine hesitant have had their hesitancy enhanced by a variety of things that are happening right now, particularly the unfortunate mix of science and politics," Collins said at an event hosted by the National Academies of Sciences, Engineering and Medicine.
"I don't want to have us, a year from now, having a conversation about how we have in our hands the solution to the worst pandemic of more than 100 years, but we haven't been able to actually convince people to take charge of it," Collins said.
People need to understand that if not enough people get vaccinated, a vaccine won't help reduce the spread of the virus, Dr. Anthony Fauci, the nation's top infectious disease official, told the Wall Street Journal in September.
"It's a combination of how effective a vaccine is and how many people use it," he said. "If you have a vaccine that is highly effective and not enough people get vaccinated, you're not going to realize the full, important effect of having a vaccine."