Fully vaccinated adults can harbour virus levels as high as unvaccinated people if infected with the Delta variant, according to a sweeping analysis of UK data, which supports the idea that hitting the threshold for herd immunity is unlikely.
There is abundant evidence that Covid vaccines in the UK continue to offer significant protection against hospitalisations and death. But this new analysis shows that although being fully vaccinated means the risk of getting infected is lower, once infected by Delta a person can carry similar virus levels as unvaccinated people.
The implications of this on transmission remain unclear, the researchers have cautioned. “We don’t yet know how much transmission can happen from people who get Covid-19 after being vaccinated – for example, they may have high levels of virus for shorter periods of time,” said Sarah Walker, a professor of medical statistics and epidemiology at the University of Oxford.
“But the fact that they can have high levels of virus suggests that people who aren’t yet vaccinated may not be as protected from the Delta variant as we hoped.”
Positive tests, hospitalisations and deaths linked to Covid have been rising slowly in the UK recently. In the week to 18 August, 211,238 people had a confirmed positive test result, an increase of 7.6% compared with the previous seven days. Over the same period, there have been 655 deaths within 28 days of a positive test, a rise of 7.9% versus the previous seven days. Hospitalisations have also risen slightly, with 5,623 going into hospital with coronavirus between 8 August 2021 and 14 August 2021, a rise of 4.3% compared with the previous seven days.
The study, which is yet to be peer-reviewed, found vaccine performance has waned against Delta versus the previously dominant Alpha variant.
The analysis did not directly investigate whether the lower level of vaccine protection against Delta affected jabs’ ability to prevent severe disease. However, Dr Penny Ward, a visiting professor in pharmaceutical medicine at King’s College London, noted: “The low incidence of hospitalisation seen to date suggests that in this respect at least the vaccines are protecting individuals from developing severe Covid.”
The study – conducted by Oxford researchers in partnership with the Office for National Statistics and the Department of Health and Social Care – compared the results of about 2.6m nose and throat swabs taken from more than 384,500 adults between December 2020 and mid-May 2021, and more than 811,600 test results from 358,983 adults between mid-May and 1 August 2021 (the period of Delta’s domination).
The UK findings on peak virus levels after Delta infections in vaccinated people echoed data from a small study cited by the US Centers for Disease Control and Prevention (CDC) last month. The agency indicated those findings had underpinned its decision to recommend that people wear masks in some indoor settings, regardless of their vaccination status, especially in areas of “substantial or high” virus transmission.
In a new study, scientists with the University of Florida have found that a combination of silver nanoparticles and antibiotics is effective against antibiotic-resistant bacteria. The researchers hope to turn this discovery into viable [...]
Peritoneal cancer is difficult to treat and has a poor survival prognosis. But a new and effective nanomedicine delivery system is offering some hope. The company is called NaDeNo and is well underway with [...]
According to a new study by researchers at Penn Medicine, ketamine, which is well-known as an anesthetic and is becoming increasingly popular as an antidepressant, dramatically reorganizes activity in the brain, almost as if [...]
A new immunotherapy releases cancer-killing cytokines only within the tumor. Researchers at the University of California San Francisco (UCSF) have developed a new T cell-based immunotherapy that selectively targets cancer cells, producing a powerful anti-cancer cytokine [...]
An AI was tasked with creating proteins with anti-microbial properties. Researchers then created a subset of the proteins and found some did the job. An AI has designed anti-microbial proteins that were then tested [...]
Treating cancer with combinations of drugs can be more effective than using a single drug. However, figuring out the optimal combination of drugs, and making sure that all of the drugs reach the right [...]
By one unique metric, we could approach technological singularity by the end of this decade, if not sooner. A translation company developed a metric, Time to Edit (TTE), to calculate the time it takes for professional [...]
Phase transition in early universe changes strength of interaction between dark and normal matter. Dark matter remains one of the greatest mysteries of modern physics. It is clear that it must exist, because without [...]
Summary: Researchers have developed a new family of nano-scale capsules capable of carrying CRISPR gene editing tools to different organs of the body before harmlessly dissolving. The capsules were able to enter the brains of [...]
An enzyme that defends human cells against viruses can help drive cancer evolution towards greater malignancy by causing myriad mutations in cancer cells, according to a study led by investigators at Weill Cornell Medicine. The [...]
Using a mouse model, Japanese researchers unleash the likely mechanism of action of Actinidia arguta (sarunashi) juice on lung cancer development. Lung cancer is a leading cause of death in Japan and across the [...]
When used as wearable medical devices, stretchy, flexible gas sensors can identify health conditions or issues by detecting oxygen or carbon dioxide levels in the breath or sweat. They also are useful for monitoring [...]
Novel drugs, such as vaccines against covid-19, among others, are based on drug transport using nanoparticles. Whether this drug transport is negatively influenced by an accumulation of blood proteins on the nanoparticle’s surface was [...]
The costly lesson from COVID: why elimination should be the default global strategy for future pandemics
Imagine it is 2030. Doctors in a regional hospital in country X note an expanding cluster of individuals with severe respiratory disease. Rapid whole-genome sequencing identifies the disease-causing agent as a novel coronavirus. Epidemiological [...]
A predictive model has been developed that enables researchers to encode instructions for cells to execute. Scientists at the University of California, San Francisco (UCSF) and IBM Research have created a virtual library of thousands of “command sentences” [...]
It's "lights out" for antibiotic-resistant superbugs as next-generation light-activated nanotech proves it can eradicate some of the most notorious and potentially deadly bacteria in the world. Developed by the University of South Australia and [...]