The vaccine is derived from the most commonly circulating strain of rotavirus, and also offered good protection against some other strains across the two-year period.

这种疫苗是根据最常见的轮状病毒毒株制成的，而且在两年的时间里也能很好地保护人体不受其它一些毒株的感染。

youdao

That said, it is still possible to get the flu, (a different circulating strain), but the chances are much less likely.

FORBES: 2013 Flu Season: How to Protect Yourself

Mr Reddy stressed that there were no signs of a tamiflu-resistant strain of H1N1 circulating in the community.

BBC: Tamiflu

People who live in institutions, such as a university, school or hospital, are particularly prone to getting any new strain that is circulating.

BBC: The flu virus that nearly killed me