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H3N2 mutation in egg-based vaccines lowered effica

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arirish View Drop Down
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    Posted: November 08 2017 at 5:58pm
Study: H3N2 mutation in egg-based vaccines lowered efficacy

In experiments designed to discover reasons for the relatively low effectiveness of last season's flu vaccine against the H3N2 strain—despite what experts thought was a close match between the vaccine strain and circulating viruses—researchers found that the culprit was a mutation that arose during production when the virus was passaged in chicken eggs.

Researchers based at the University of Pennsylvania reported their findings yesterday in Proceedings of the National Academy of Sciences (PNAS). They found that the egg-adapted virus lacked a key glycosylation site on the hemagglutinin protein. The findings raise concerns, because the same H3N2 vaccine strain is in the 2017-18 flu vaccines and may again provide an underwhelming level of protection. Also, the investigators said the findings underscore ongoing problems with producing flu vaccine antigen in eggs and that antigens grown in systems other than eggs are more likely to protect against H3N2 viruses that are currently circulating.

As part of their study, the scientists found that antibodies elicited in ferrets and humans exposed to the egg-produced 2016-17 H3N2 strain did a poor job neutralizing the viruses that circulated last flu season. However, antibodies elicited in ferrets infected with the current circulating H3N2 strain and humans vaccinated with an H3N2 vaccine produced in a non-egg system were able to recognize and neutralize the new H3N2 virus.

On Oct 23, some of the same researchers were part of another study team based at Scripps Research Institute that described the structure of the mutation using x-ray crystallography. They reported their findings in PLoS Pathogens.

Scott Hensley, PhD, coauthor of both studies and associate professor of microbiology at the University of Pennsylvania's Perelman School of Medicine, said in press release from the school, "Our data suggest that we should invest in new technologies that allow us to ramp up production of influenza vaccines that are not reliant on eggs." Though the flu season could be another difficult one if H3N2 viruses dominate again, he said people should still get vaccinated, because some protection against H3N2 is better than nothing and the H1N1 and influenza B components will likely provide excellent protection.

On Oct 23, some of the same researchers were part of another study team based at Scripps Research Institute that described the structure of the mutation using x-ray crystallography. They reported their findings in PLOS Pathogens.

Yesterday Stat News contacted several experts about current options for producing vaccines that are less likely to contain mutations introduced during the production process and obstacles to moving manufacturing away from eggs entirely. The US government has supported other flu vaccine platforms: a recombinant vaccine (FluBlok) from Protein Sciences and a cell-based vaccine (Flucelvax) made by Seqirus. Experts said obstacles include the expense and regulatory hurdles of shifting to another production method, especially since for now there is little evidence that those flu vaccines are better.

http://www.cidrap.umn.edu/news-perspective/2017/11/news-scan-nov-08-2017

Nov 6 PNAS study:
http://www.pnas.org/content/early/2017/10/31/1712377114.abstract
Buy more ammo!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote carbon20 Quote  Post ReplyReply Direct Link To This Post Posted: November 10 2017 at 2:08pm
watch the shares of those companies rocket.............

i am a cynic........

governments will be sucked into throwing Billions in a money pit.............
12 Monkeys...............
1995 ‧ Science fiction film/Thriller ‧ 2h 11m a must for AFT
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