“If you aren’t vaccinated, you must wear a mask throughout flu season, or be fired!”
But what if you are in the 45-55% of healthcare workers who got vaccinated but lack immunity to circulating flu strains? Shouldn’t you be wearing a mask too?
What if you are in the 75-100% of vaccinated workers who get no protection some years (like last year) because the vaccine was a poor match to the strains that actually circulated? Shouldn’t you be wearing masks, if the idea for the masks is to protect patients?
Not that there are any data suggesting a mask helps prevent the spread of flu when the wearer is not actively coughing or sneezing.
The European Center for Disease Prevention and Control, which may be more forthcoming about flu than CDC, points out flu vaccine effectiveness is thought to be in the 50% range this year, better than last year:
The vaccine effectiveness of the 2012/13 influenza vaccine is expected to be higher against influenza A(H3) infection than the especially low levels observed in Europe for the 2011/12 season. First indications from the UK confirm this although the estimates are still only in the range of 45% to 55%.
Also from the European Center, it appears the Europeans are so unconcerned about the need for HCW vaccinations they fail to even track them! They don’t trust the US/ CDC figures for vaccine effectiveness, either.
Influenza Vaccine Coverage
Seasonal vaccine coverage data are not yet available from the VENICE project* for the 2012/13 season. From the questionnaire, Latvia reported a lower proportion of people vaccinated while the UK (England) reported vaccination coverage comparable to 2011/12. Preliminary results from England estimate an uptake of >70% among those aged ≥65 years and around 50% in those under 65 years old in a clinical risk group, with a much higher uptake among pregnant women than during the previous season. Among the nursing homes affected by ARI outbreaks in France, the vaccine coverage (81%) was the lowest observed since 2003/04. This proportion is still to be confirmed, but it could reflect a lower national vaccine coverage among older people this season. The UK (Scotland) reported an increased uptake by pregnant women; 48.3% in those without risk factors and 64.6% in those with risk factors. Norway mentioned low vaccination coverage in risk groups. There is no information on immunisation of healthcare workers. Overall, it should be noted that there have been small declines in vaccine coverage in older age groups (the only risk group with consistent data) in a number of EU countries since the 2007/08 season …
Vaccine effectivenessA recent American study  published an early estimate of influenza vaccine effectiveness non-adjusted for age of 62% (95% CI: 51%–71%) for 2012/13 which is better than for the previous season in the United States. A study from Canada showed somewhat lower levels . However, it is essential to note that the US estimates were not adjusted for age, risk groups and other confounders and the proportions of circulating viruses in the USA and the EU are quite different this season: there are few A(H1N1) viruses circulating in the USA. Also, the analytic approach is different; in Europe the focus is more on effectiveness in the high risk groups. Hence, the US percentage should be interpreted with caution and may not reflect the vaccine effectiveness in Europe or for high risk groups. Early estimates of vaccine effectiveness in the UK have shown an overall adjusted vaccine effectiveness of 51% (CI: 27%–68%) with 49% against influenza A alone and 52% against influenza B.