"People are getting scared. It has really taken us by surprise."
Speaking from her hometown in Houston, Texas, Rebecca* says her city is facing a new wave of Covid-19 infections, just as many Americans thought the virus had finally been brought under control.
The 22-year-old told news.com.au that the increase in coronavirus cases has blindsided many locals, amid a warning that a new, even deadlier variant could soon emerge if vaccination rates don't increase fast.
"More people have been getting vaccinated here and the number of people getting Covid had dropped," she said.
"Everyone was starting to feel more a bit more relaxed. And then, bam, the cases started increasing again.
"It's really unbelievable. And I think the problem is that the vaccination rates aren't high enough. Now, hospitals are filling up again.
"It's a really huge shock for everyone here to be on high alert again. It's exhausting."
Rebecca is far from alone in this situation, as the US has been left reeling after recording its highest number of Covid-19 cases since the vaccine rollout began.
The US announced 100,000 new Covid cases on Sunday, compared to around 11,000 daily cases in June. It recorded 250,000 cases per day in January during its peak winter wave, the NY Post reports.
Weekly cases passed 750,000 on Friday, the most since early February. Meanwhile, deaths and hospitalisations are also rising, with more than 44,000 Americans hospitalised from Covid-19, according to the Centers for Disease Control and Prevention.
While this is still well under the pre-vaccine peak in January, which saw more than 120,000 Americans hospitalised, it's a whopping 40 per cent increase in a one-week period, and a 400 per cent increase since June.
Nearly 500 deaths are being recorded in the US every day due to the virus, that's compared to 270 deaths a fortnight ago. Deaths peaked at 3500 per day in January.
The latest surge has many gobsmacked – even with vaccination rates rising, the US has found itself reaching a six-month high when it comes to Covid-19 cases. So what's gone wrong?
Vaccination challenges amid fears of a new variant
The US is dealing with the same problem much of the world is also grappling with – the emergence of new variants such as Delta which are much more transmissible.
Also, vaccinations rates, while in most US states are much higher than in New Zealand, are still not enough to reach herd immunity and eradicate the virus.
Currently, 50 per cent of Americans are fully vaccinated against Covid, according to the White House. While that's impressive compared to Australia's rate of 17 per cent and New Zealand's rate of just over 15 per cent, there are fears it still just isn't enough.
There are reportedly 93 million US residents who are eligible to get vaccinated who haven't yet been. Also, many people may get infected or reinfected with Covid even when vaccinated, although they are likely to get a milder form of the illness.
You don’t get an effect much clearer than this in science/medicine — US states with higher vaccination rates have lower cases/hospitalizations, and vice versa.
"It clearly has taken a very bad turn," Anthony Fauci, chief medical adviser to US President Joe Biden, told Bloomberg this week of the nation's Covid-19 spike.
"As long as you have virus freely circulating in society the way it's doing now with 100,000 cases a day, you give ample opportunity for the virus to continue to mutate."
He said the high numbers are concentrated in certain areas with low vaccination rates, and the states of Texas and Florida are accounting for a disproportionately high proportion of the infections, at approximately 40 per cent.
Also, if the US fails to get control of the coronavirus, Fauci warned it could mutate into an even more concerning variant.
"It is conceivable that that could mutate into a variant that's even more problematic than the Delta variant. So I'm concerned on two fronts, on what's going on now and what could conceivably happen if we don't get control of this virus."
The longer people remain unvaccinated, the more likely the virus is to mutate into a variant that's "even more problematic" than delta, Dr. Anthony Fauci tells Quicktake's @MadisonMills22pic.twitter.com/mDiQqWDfFd
Meanwhile, a clearly worried US President Joe Biden has taken to Twitter to issue a plea for citizens to get vaccinated as the Delta variant grips the nation.
The Delta variant is surging, but we have the power to stop it.
In Texas, there have been 3.2 million Covid cases recorded so far, and 53,000 deaths. Currently there are reportedly more than 7600 people in the hospital with coronavirus in the state.
Chief State Epidemiologist Jennifer Shuford from the Texas Department of State Health Services said there is cause for concern.
"We've been living this pandemic now for a year-and-a-half," Shuford told the Houston Public Media.
"We thought we had seen the worst of it with those first two pandemic waves that we experienced. This third wave that we're having right now in Texas is showing a very steep increase in cases and hospitalisations, as great or even steeper than what we were seeing with those first two waves."
She said the case counts are increasing at an "astonishing rate".
"The problem with that is that hospitals usually get prepared when they think flu and pneumonia season is coming up," Shuford said.
"They make sure their staffing is ready, and that their ICUs are ready. And with this steep increase in cases and hospitalisations that we're seeing, people just weren't prepared."
In Houston this week, Texas Medical Center CEO Bill McKeon said a majority of people hospitalised are unvaccinated.
"Hospitalisations across the Texas Medical Center are escalating at a pace we have not observed since the highest Covid-19 peak in summer 2020," McKeon said.
"The impact of unvaccinated individuals is widespread and encouraging the continued spread of Covid-19."
As of Sunday there were 439,041 confirmed cases of Covid-19 in Houston/Harris County and 5101 deaths, while 350,987 people have been fully vaccinated.
Frustration in Florida
The biggest problem is occurring in Florida, which has become the epicentre of the Covid pandemic in the US.
Reeling from a surge of cases due to the Delta variant, around 135,000 Florida residents have tested positive to Covid in the last week, an increase of 22 per cent since the week prior, according to data from the Florida Department of Health.
Also, hospitalisations in Florida have reached their peak in the pandemic this week with more than 12,864 Covid patients admitted.
Overrun with patients, the Florida Hospital Association expects more than half of the state's hospitals to face a "critical staffing shortage" within the next week.
Despite the rising case numbers, Florida Governor Ron DeSantsis encouraged residents to get vaccinated but refused to impose a new mask rule, also stating that lockdowns "fail time and time again".
Astoundingly, while Florida has less than 7 per cent of the US population, it has recorded one fifth of the nation's covid cases in the last fortnight.
Approximately half of Florida's population has been fully vaccinated, and this number needs to be boosted quickly.
"Despite the information that's coming out about people that are fully vaccinated still getting Covid, those numbers are low," Dr. George Ralls, senior vice-president and chief medical officer of Orlando Health, said of those worried about still catching Covid-19 despite being vaccinated.
"And they are absolutely still in a better situation than they would have been had they gotten Covid without the vaccine. So (it's) really, really important to drive that message to everybody."
Good news in the UK
Meanwhile in Britain, the number of new Covid cases has surprisingly halved in just two weeks.
On July 17, two days before Britain's "Freedom Day", cases hit a peak of 54,674. Many predicted the cases would rise to 100,000 a day, and are now scratching their heads as the daily cases dropped to around 26,000
Experts suggest that the warm weather and early start to the school holidays for some were among the reasons why the infection rate has lowered.
With a vaccination rate of 70 per cent, Public Health England epidemiologist Meaghan Kall told the Guardian that data from antibodies suggested most age groups were getting "very close to herd immunity".
However, other factors that may weigh into this are the decline in people getting tested, and many people remaining cautious when outside of the home, with mask wearing and social distancing remaining common.