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delta variant: Pfizer, AstraZeneca vaccines protect against Delta variant: Lancet study

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LONDON: The Delta variant of coronavirus, first identified in India, doubles the risk of hospitalisation compared with the Alpha variant first found in the UK, but Pfizer and AstraZeneca vaccines provide good protection against the strain, says a study published in The Lancet journal.
Researchers at Public Health Scotland and the University of Edinburgh, UK, found that the Pfizer-BioNTech vaccine offered better protection against the Delta variant compared to the Oxford-AstraZeneca preventive, known as Covishield in India.
The analysis covered the period from April 1 to June 6, 2021, for the demographic distribution of cases.
The team analysed 19,543 confirmed SARS-CoV-2 infections over the period of interest, of whom 377 were admitted to hospital for Covid-19 in Scotland.
Around 7,723 community cases and 134 hospitalisations were found to have the Delta variant of coronavirus.
The study found that the Pfizer vaccine offered 92 per cent protection against the Alpha variant and 79 per cent against the Delta strain two weeks after the second dose.
For AstraZeneca’s vaccine, there was 60 per cent protection against Delta compared with 73 per cent for Alpha variant, the researchers said.
They also found that two doses of vaccine provide much better protection against the Delta variant compared to a single dose.
“Risk of Covid-19 hospital admission was approximately doubled in those with the Delta variant of concern (VOC) when compared to the Alpha VOC, with risk of admission particularly increased in those with five or more relevant comorbidities,” the authors of the study noted.
“Both the Oxford–AstraZeneca and Pfizer–BioNTech Covid-19 vaccines were effective in reducing the risk of SARS-CoV-2 infection and Covid-19 hospitalisation in people with the Delta VOC,” they said.
However, the researchers noted that these effects on infection with Delta variant appeared to be diminished when compared to those with the Alpha VOC.
The authors of the study warned that the vaccine comparison should be interpreted with caution due to differences in the groups which received each type of vaccine, and also in how quickly immunity is developed with each shot.





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Sinopharm Covid-19 vaccines appear safe, effective, says study

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JAKARTA: Two vaccines made by China’s Sinopharm appear safe and effective against COVID-19, according to a study published in a medical journal.
Scientists had been waiting for more details about the two vaccines, even though they already are being used in many countries, and one recently won the backing of the World Health Organisation for emergency use.
The report, published online in the Journal of the American Medical Association, concluded the two vaccines are about 73 per cent and 78 per cent effective, as Sinopharm has previously claimed.
Researchers from Sinopharm and its local partners in the Middle East say the trial involved around 40,380 participants with the company’s two vaccines — one developed by the Wuhan Institute of Biological Products and the other by the Beijing Institute of Biological Products — and a placebo.
The trial was carried out in four countries — Bahrain, the United Arab Emirates, Egypt and Jordan. However, the study provided data for just Bahrain and the UAE.
“There’s nothing very surprising. It’s consistent with what they have claimed previously, but it does not completely eliminate the doubts about Sinopharm,” said Jin Dong-yan, a medical professor at the University of Hong Kong who was not involved with the study.
He raised doubts about how protective the vaccine was based on a recent surge of cases in the island nation of Seychelles, which had vaccinated a large majority of its population with the Sinopharm vaccine.
The study, performed mostly in younger men, had little information about the vaccine’s effectiveness against severe disease. Some experts also expressed concern at the shortage of female participants, with nearly 85 per cent being male.
“It’s important to make sure you have tested it in enough women to be able to start seeing any possible safety concerns,” said Ashley St. John, an associate professor at Duke-NUS Medical School in Singapore.
A spokesperson for the company did not immediately respond to a request for comment.
The vaccines, both of which are made with inactivated viruses, have already been given to millions of people across the world.
The World Health Organisation cleared the Beijing Institute of Biological Products’ shot for emergency use in early May, making it the first Chinese vaccine to receive the certification.
Chinese Foreign Minister Wang Yi said in April that China has provided vaccines to more than 100 countries, although it has not identified them. While China has six vaccines in use, the majority of its exports come from two companies: Sinopharm and Sinovac.





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Pfizer, Moderna vaccines may greatly reduce risk of asymptomatic Covid-19 infection, study says

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WASHINGTON: Patients without Covid-19 symptoms are far less likely to test positive, and unknowingly spread Covid-19 ten days after receiving a second dose of a messenger RNA vaccine, compared to those who have not been vaccinated, a study says.
Researchers from Mayo Clinic in the US noted that several vaccines are now clinically available under emergency use authorisation and have demonstrated efficacy against symptomatic Covid-19.
However, the impact of vaccines on asymptomatic SARS-CoV-2 infection is largely unknown, they said.
The Pfizer-BioNTech and Moderna messenger RNA (mRNA) vaccines for Covid-19 are authorised for emergency use in many countries.
An mRNA vaccine is based on the segments of the genetic material, or RNA, of the novel coronavirus.
With two doses of a mRNA Covid-19 vaccine, people with no symptoms showed an 80 per cent lower adjusted risk of testing positive for the disease after their last dose, according to the researchers.
The findings, published in the journal Clinical Infectious Diseases, underscore the efficacy of mRNA vaccines for Covid-19 to significantly limit the spread of Covid-19 by people with no symptoms who may unknowingly spread the infection to others.
“We found that those patients without symptoms receiving at least one dose of the first authorised mRNA Covid-19 vaccine, Pfizer-BioNTech, 10 days or more prior to screening were 72 per cent less likely to test positive,” said Aaron Tande, a Mayo Clinic infectious diseases specialist and co-first author of the paper.
“Those receiving two doses were 73 per cent less likely, compared to the unvaccinated group,” Tande said.
After adjusting for a range of factors, researchers found an 80 per cent risk reduction of testing positive for Covid-19 among those with two doses of an mRNA Covid-19 vaccine.
The researchers retrospectively looked at a cohort of 39,000 patients who underwent pre-procedural molecular screening tests for Covid-19.
Over 48,000 screening tests were performed, including 3,000 on patients who had received at least one dose of an mRNA Covid-19 vaccine, they said.
According to the researchers, these screening tests were part of routine Covid-19 testing prior to treatments not related to Covid-19, such as surgeries and other procedures.
Patients in the vaccinated group had received at least one dose of a messenger RNA Covid-19 vaccine, they added.



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