Big study shows breakthrough infections are less severe
A UK study of over a million participants has found that people who have been vaccinated are significantly less likely to get symptomatic COVID-19, and less likely again for it to be severe.
The study examined data from 1,240,009 people who’d had at least one dose of the AstraZeneca, Pfizer or Moderna vaccines, 971,504 of whom had received two doses. During the study period, a small percentage of the group tested positive to COVID-19 after both doses – 0.5% caught it after one dose, and 0.2% after two.
If they did test positive, people who had received one dose of a vaccine were 63% more likely to be asymptomatic, and fully vaccinated people were 94% more likely. Fully vaccinated people who’d caught COVID were also 50% less likely to have long COVID – defined in this study as symptoms lasting longer than 28 days.
“We are at a critical point in the pandemic as we see cases rising worldwide due to the Delta variant. Breakthrough infections are expected and don’t diminish the fact that these vaccines are doing exactly what they were designed to do—save lives and prevent serious illness,” says Dr Claire Steves of King’s College London, UK, lead author on a paper describing the study in The Lancet Infectious Diseases.
“Our findings highlight the crucial role vaccines play in larger efforts to prevent COVID-19 infections, which should still include other personal protective measures such as mask-wearing, frequent testing, and social distancing.”
New variant in South Africa
South African scientists have described a potential new variant of interest in a preprint (not peer-reviewed) paper. First detected in May 2021, the variant – currently called C.1.2 – has popped up in seven other countries, and the authors say it has mutations in common with all four variants of concern (Alpha, Beta, Gamma and Delta) as well as some extra mutations.
As yet, the World Health Organisation hasn’t listed it as a variant of interest or a variant of concern, so it doesn’t get a Greek letter for now.
“Very little data is currently available on the C.1.2 variant; we are awaiting further studies to characterise it,” says Dr Megan Steain, a lecturer in Immunology and Infectious Diseases at The University of Sydney, who has not been involved with the research.
“As long as there are new infections with SARS-CoV-2, the virus will evolve. New variants will emerge and it is important to monitor them. However, not every variant survives, and many die out despite containing mutations which might suggest otherwise.”
“Similar concerns were expressed about the Iota variant first detected in New York, and that was swiftly overtaken by the Delta variant,” adds Professor Adrian Esterman, chair of Biostatistics at the University of South Australia, who was also not involved in the study.
“I think that we should remain calm, let the excellent South African virologists do their work, and watch carefully what happens over the next few weeks.”
Don’t just trust your intuition on COVID information
According to research from the Australian National University, people who think based on their first instincts are more likely to believe and share COVID misinformation.
The researchers showed 742 Australians a mixture of debunked and accurate statements about COVID-19, and then tested the participants’ thinking styles.
Participants who gave intuitive answers were significantly worse at spotting the difference between truth and misinformation.
“Knowing that a reliance on intuition might be at least partly responsible for the spread of COVID-19 misinformation gives science communicators important clues about how to respond to this challenge,” says Matthew Nurse, a PhD researcher at the Centre for the Public Awareness of Science at ANU, and lead author on a paper describing the research, published in Memory & Cognition.
“For example, simply reminding people to take their time and think through dodgy claims could help people reject misinformation and hopefully prevent them from following ineffective or dangerous advice.”
mRNA vaccines get a response in most immunocompromised people
Vaccine efficacy can be unreliable for immunocompromised people, but a US study in the Annals of Internal Medicine has shown that nearly 90% of immunocompromised patients had an antibody response after getting an mRNA vaccine.
The researchers examined blood samples from 133 immunocompromised people, as well as 53 immunocompetent people, two weeks after each person had been immunised.
While the immunocompromised participants didn’t have as strong a reaction as the control group, 88.7% of them still developed antibodies in response to the vaccine.
The researchers say their findings should encourage immunocompromised people to get vaccinated.
A third of people became less active in lockdown
During lockdown, 29% of English people reduced their physical activity while 9% of people increased it, according to a paper in Scientific Reports.
The study tracked 35,915 adults in England from March to August 2020. Participants were asked to report their physical activity each week.
The researchers, who are based at University College London in the UK, noted a steady increase in the number of participants who hadn’t done any physical activity over the study period. However, they note that 62% of their sample didn’t change their physical activity levels during lockdown.
Unsurprisingly, the researchers advocate for more physical activity as a result of their study. “More public health efforts should be made to promote physical activity for the general population,” they conclude in their paper.
Ellen Phiddian is a science journalist at Cosmos. She has a BSc (Honours) in chemistry and science communication, and an MSc in science communication, both from the Australian National University.
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