Work started this week on next season’s flu vaccine (疫苗), with experts working out forecasts about w
英语试题 08-29
Work started this week on next season’s flu vaccine (疫苗), with experts working out forecasts about which types of the flu virus will be making the rounds. But don’t expect any improvements. Flu experts are already admitting that most vaccines will give at best basic protection, because they’re based on old-fashioned technology. It’s not a new problem, but one that the slow-moving world of drug and vaccine production seems helpless to improve upon.
Every flu vaccine is a cocktail, aimed at either three or four of the most common flu types. Flu vaccines must be recreated every year because flu viruses develop constantly in a process called antigenic drift. In February, global flu experts gather to trade notes on what viruses are circulating in different countries and to come to an agreement on which types the next vaccines should be made to target.
In recent years, flu vaccines have been based on H1N1, H3N2 and either one or two types of influenza B virus. Each of these has a “reference” type, which is used to make seed virus. Producers add the seed types to eggs and incubate (孵) them as the virus grows. Then they purify the virus, and either weaken it or kill it to make a vaccine.
Using eggs is a tricky (=difficult) and unpredictable process. Sometimes the virus doesn’t grow well in eggs, which can mean less vaccine than expected. The result is a flu vaccine that doesn’t offer much protection. “As long as we have eggs we are going to have this problem,” said Scott Hensley, a flu virus expert, “The only solution is not to depend on eggs.”
Flu is a major killer. The 2017-2018 season has been a severe one, hitting the entire U. S. with widespread influenza infection (感染) at once for weeks on end, and killing 97 children so far. Against this threat, even a less satisfying flu vaccine will definitely help. “Even when you have these mismatches it will not prevent infection but likely prevent disease severity,” said Hensley.
8. Next season flu vaccine fails to improve because ______.
A. it has offered the best protection
B. experts can’t forecast the flu types
C. it is based on outdated technology
D. experts are unwilling to respond to changes
9. According to Paragraph 2, flu experts ______ in February.
A. exchange views on the virus types next season
B. get together and make a deal on vaccines
C. sign an agreement on vaccine production
D. decide on how to circulate the viruses
10. The risk of using eggs to make vaccines may be that ______.
A. seeds are less likely to get protection
Every flu vaccine is a cocktail, aimed at either three or four of the most common flu types. Flu vaccines must be recreated every year because flu viruses develop constantly in a process called antigenic drift. In February, global flu experts gather to trade notes on what viruses are circulating in different countries and to come to an agreement on which types the next vaccines should be made to target.
In recent years, flu vaccines have been based on H1N1, H3N2 and either one or two types of influenza B virus. Each of these has a “reference” type, which is used to make seed virus. Producers add the seed types to eggs and incubate (孵) them as the virus grows. Then they purify the virus, and either weaken it or kill it to make a vaccine.
Using eggs is a tricky (=difficult) and unpredictable process. Sometimes the virus doesn’t grow well in eggs, which can mean less vaccine than expected. The result is a flu vaccine that doesn’t offer much protection. “As long as we have eggs we are going to have this problem,” said Scott Hensley, a flu virus expert, “The only solution is not to depend on eggs.”
Flu is a major killer. The 2017-2018 season has been a severe one, hitting the entire U. S. with widespread influenza infection (感染) at once for weeks on end, and killing 97 children so far. Against this threat, even a less satisfying flu vaccine will definitely help. “Even when you have these mismatches it will not prevent infection but likely prevent disease severity,” said Hensley.
8. Next season flu vaccine fails to improve because ______.
A. it has offered the best protection
B. experts can’t forecast the flu types
C. it is based on outdated technology
D. experts are unwilling to respond to changes
9. According to Paragraph 2, flu experts ______ in February.
A. exchange views on the virus types next season
B. get together and make a deal on vaccines
C. sign an agreement on vaccine production
D. decide on how to circulate the viruses
10. The risk of using eggs to make vaccines may be that ______.
A. seeds are less likely to get protection
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