(CNN) The pace of people getting first doses of Covid-19 vaccines is the slowest it has been since July 23, according to data released Wednesday from the US Centers for Disease Control and Prevention.
The data comes as flu season is around the corner, which could increase death tolls and put more strain on hospitals already struggling with an influx of patients and depleted resources.
More than 312,000 people have initiated the vaccination process -- gotten their first shot -- over the last week, CDC data shows. That's a 7% drop from last week and a 35% drop from the previous month.
The average number of all doses given each day, including second doses, was 742,703 over the past week -- 19% below where it was at the start of this month but still higher than the end of July.
About 182 million people, or 54.9%, of the US population, are fully vaccinated, the data shows. That leaves 71 million people, or 25.1% of the eligible population, who are not vaccinated.
"We are bracing ourselves for an awfully busy winter ahead," Dr. Megan Ranney, associate dean of the School of Public Health at Brown University, told CNN on Tuesday.
The country is once again at a point where an average of more than 2,000 people are dying of Covid-19 every day, according to data from Johns Hopkins University.
And hospitals are straining to keep up with the number of patients coming in. Staff shortages and employee fatigue in Pennsylvania hospitals have reached a point where some health systems are offering signing bonuses, loan forgiveness and other incentives to staff. In Wyoming, nearly 100 members of the state's National Guard were activated Tuesday to assist hospitals dealing with the surge.
And though it isn't clear yet what this year's flu season has in store, it could add additional stress to an already pressed health care system.
"Flu is still a killer, not as much as Covid-19, but between 12,000 and 50,000 Americans lose their lives every year from flu," said Dr. Peter Hotez, vaccinologist and dean of the National School of Tropical Medicine at Baylor College of Medicine.
Flu numbers were actually relatively low last year, but experts said that doesn't necessarily foreshadow how this year will turn out.
"Let's be clear on why flu cases were so low last year, it's because we were all masked and we were all distancing," Ranney said. "Those things are not being done anymore in the vast majority of the country."
Vaccines are the surest way to get the pandemic under control, experts have said, but rates are still lower than they need to be. Health officials are now asking the public to get both their Covid-19 vaccines and flu shot.
Pediatricians recommend that both adults and children 6 months and older receive their flu vaccinations by Halloween, Dr. Flor Munoz, a pediatric infectious disease specialist at Texas Children's Hospital, told CNN.
Some vaccine clinics around the country are offering both shots -- and encouraging people who come in for one to make sure they have the other.
"If somebody comes in wanting the flu vaccine and they haven't had a Covid vaccine then we can encourage them to get both, or vice-versa," said Dr. Robert Hopkins, chief of general internal medicine at the University of Arkansas for Medical Sciences and chair of the National Vaccine Advisory Committee.
If health care providers can encourage people to do both, "We potentially are going to have a greater impact on both disease prevention efforts," Hopkins said.
Pfizer has suggested a third dose of its vaccine will boost protection for those already vaccinated, and now Johnson & Johnson has announced an extra dose of its vaccine is helpful as well.
A two-dose version of the vaccine provides 94% protection against symptomatic infection, the company said Tuesday -- making a two-dose regimen of J&J's Janssen vaccine comparable to a two-dose regimen of Moderna's or Pfizer's.
Johnson & Johnson's single-dose vaccine was given emergency use authorization by the US Food and Drug Administration on February 27. It has been given to about 14.8 million Americans, according to the CDC.
The company released some details of three studies looking at various aspects of its Janssen vaccine, and said that, taken together, they showed the vaccine provided long-lasting protection that could be boosted with an extra shot.
"Our single-shot vaccine generates strong immune responses and long-lasting immune memory. And, when a booster of the Johnson & Johnson COVID-19 vaccine is given, the strength of protection against COVID-19 further increases," Dr. Mathai Mammen, global head of Janssen Research & Development, said in a statement.
The company's ongoing Phase 2 trial of a two-dose regimen showed giving two doses 56 days apart provided 100% protection against severe Covid-19 and 94% protection against moderate to severe Covid-19 in the US.
A second study showed people given a booster shot six months or longer after their first dose had a 12-fold increase in antibodies -- compared to a four-fold increase for people who got a second dose at two months. So, protection should be stronger if people get boosters later, Dr. Dan Barouch, head of Beth Israel Deaconess' Center for Virology and Vaccine Research, told CNN.
The protection provided by Covid-19 vaccines appears to wane over time, especially for people 65 and older, a CDC expert said Wednesday.
"For individuals 65 plus, we saw significant declines in VE (vaccine effectiveness) against infection during Delta for the mRNA products," said Ruth Link-Gelles, who helps lead the CDC's Vaccine Effectiveness Team.
Link-Gelles reviewed a series of studies looking at the overall effectiveness of vaccines in various groups between February and August and found similar patterns for Pfizer's and Moderna's vaccines, both made using mRNA.
The CDC's Advisory Committee on Immunization Practices is meeting to discuss the potential need for booster doses of vaccines, and is discussing vaccine effectiveness and safety in general.
The committee will be back at 12 p.m. Thursday now that the US Food and Drug Administration (FDA) said it would grant emergency use authorization for a booster dose of Pfizer's Covid-19 vaccine in people 65 and older, people at high risk of severe disease and people whose jobs put them at risk of infection.
The average rate of Covid-19 deaths in the 10 least vaccinated states was more than four times higher over the past week than the rate in the 10 most vaccinated states, according to a CNN analysis.
In the least vaccinated states, roughly eight people out of every 100,000 residents died of Covid-19 over the past week, compared with only about two out of every 100,000 people in the 10 most vaccinated states.
CNN used data from Johns Hopkins University and the CDC for the analysis.
Less vaccinated states tend to have higher hospitalization rates, too.
The latest data from the US Department of Health and Human Services shows an average of 39 Covid-19 hospitalizations per 100,000 people in the 10 least vaccinated states, nearly three times higher than the average rate of 14 per 100,000 people in the 10 most vaccinated states.
The states with the lowest vaccination rates have fully vaccinated less than 45% of their residents. They are Alabama, Arkansas, Georgia, Idaho, Louisiana, Mississippi, North Dakota, Tennessee, West Virginia and Wyoming.
The 10 states with the highest vaccination rates have fully vaccinated more than 62% of their residents. They are Connecticut, Maine, Maryland, Massachusetts, New Jersey, New Mexico, New York, Rhode Island, Vermont and Washington.