In this illustrated picture taken on March 19, 2021, you can see vials labeled with Pfizer BioNTech, AstraZeneca, and Modern Coronavirus Disease (COVID-19) vaccines. REUTERS/Dado Ruvic/Illustration
December 8 (Reuters)-The following is a summary of some recent research on COVID-19. They include studies that require further research to confirm the results and have not yet been peer-reviewed and certified.
Mixed vaccine can boost immune response
British researchers have found that the method of mixing and matching COVID-19 vaccines is safe and effective, and some combinations can even improve the immune response.
They studied 1,079 volunteers, and their first shot was an adenovirus vector vaccine from AstraZeneca (AZN.L) or an mRNA vaccine from Pfizer (PFE.N)/BioNTech. Participants were then randomly assigned to receive the same vaccine or Moderna (MRNA.O) high-dose mRNA vaccine or experimental Novavax (NVAX.O) vaccine injection, the latter using a different technology from other vaccines.
The research team reported in The Lancet on Monday that the mixed vaccine did not produce any adverse effects. Laboratory experiments have shown that no matter which injection people receive first, getting Moderna as a second dose will produce a stronger antibody response than the second dose of the original vaccine.
The researchers found that an important second-line response from the immune system-T cell activation-is most evident in the AstraZeneca vaccine, followed by the Novavax vaccine. Given that none of these require special freezing storage, this finding — and the fact that it is safe to mix any other tested vaccine — may be “relevant to 94% of people in low-income countries who have not received any vaccines,” they concluded. road.
The accuracy of the experimental saliva test almost matches that of PCR
Researchers believe that the experimental saliva test can diagnose SARS-CoV-2 infection within minutes, almost as accurate as the gold standard PCR test.
Unless it is done immediately after a night of fasting, a typical saliva test is unreliable because the concentration of virus particles in the saliva drops sharply after eating or drinking. Like other rapid antigen tests, this test called PASPORT combines viruses with nanoparticles. But researchers reported on Microchimica Acta on Monday that PASPORT added a second type of nanoparticle, which would combine with the first group to produce a stronger signal and make detection more sensitive at any time of the day. A virus was found.
When tested on non-fasting samples from 139 volunteers — 35 known to be infected with COVID-19 and 19 with other respiratory infections — and compared to PCR testing of swab samples from the back of the nose and throat, PASPORT's accuracy in identifying SARS is 97%-CoV-2 and 91% accuracy exclude it.
“Although PCR has always been the gold standard, it requires well-trained personnel and laboratory infrastructure,” said Dr. Danny Jian Hang Tng, head of research at Singapore General Hospital and Duke-NUS Medical School in a statement. Reliable, painless, affordable and convenient saliva testing "will encourage more testing and more frequent testing."
Omicron partially evades Pfizer vaccine protection
Preliminary data indicates that the Omicron variant of the coronavirus can partially evade the protection of two doses of COVID-19 vaccine from Pfizer and BioNTech.
Researchers in South Africa exposed Omicron to antibodies in blood samples from 12 people, each of whom received two doses of the vaccine. Alex Sigal of the African Institute of Health in Durban and his colleagues reported in a paper on Tuesday that these antibodies are more effective at neutralizing Omicron than they are at neutralizing viruses that spread early in the pandemic. Ability is 41 times lower. Has been peer reviewed.
Other researchers said that in volunteers who had previously been infected with the coronavirus, the researchers found that Omicron had a "relatively high" neutralizing effect, indicating that increasing the antibody level by boosting the dose would help. Jonathan Ball, a virologist at the University of Nottingham, UK, who was not involved in the study, said in a statement that people who have been vaccinated and have been infected before “mimicking our expectations of people receiving two doses of vaccine, and Boost... The data should reassure us that the vaccine will still provide protection." The vaccine also induces second-line defense, including T cell immunity. He said: "We think this will be less affected by the Omicron mutation." On Wednesday, BioNTech and Pfizer said that although their two doses of vaccine are less effective in neutralizing Omicron, a laboratory test showed that the third dose of the vaccine can increase the level of protection to that of the original virus.
Click on Reuters' picture of the vaccine being developed.
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