This season, the flu has hit hard and early:
|Source: CDC Influenza Weekly Report, January 14, 2013|
With increased rates, is this sort of declaration helpful? With influenza already in full swing, will expanding immunization help, or is it a bit of a double-edged sword?
Almost a week ago, on January 9, Boston declared a public health emergency, with widespread transmission (700 lab-confirmed cases already in the city, compared to last season's total of 70) and 18 deaths. New York state followed suit on Saturday, after receiving 19,128 reported cases, compared to the 2011-2012 total of 4,404 confirmed cases. Other areas have also considered declaring emergencies with the aim to provide greater access to influenza immunization clinics.
Given how many cases are already circulating and spreading the virus, there is a legitimate question as to whether vaccination at this point in the game will be good or bad. In particular, what impact might it have for future immunization efforts?
There's no doubt that, if you only took one step to protect yourself and those around you, the vaccine is arguably the single best thing you can do. Hand hygiene, covering coughs and sneezes and so on are all things you should be doing, but there is a far greater chance of failure in these measures than the vaccine. Diet and nutrition may have some impact on the severity if you get sick, but won't do anything to prevent getting infected or spreading the disease. A very strong argument, then, can be made for people to go out and get immunized against this year's seasonal influenza. If they have not been exposed yet, widespread vaccination can help slow the spread.
On the flip side, for those who have not already been immunized, the chances of being exposed shortly before or after vaccination are pretty high. What does that matter? you might ask. It takes a little time for symptoms to appear after infection. And as for the vaccine itself, after getting it, it takes a person about two weeks to develop enough immunity to ward off infection. What this means is that someone who is infected just before vaccination or within that two-week window following immunization might still get the flu. This is part of the reason for the common myth that the vaccine causes influenza in some people. It doesn't, but the timing makes it seem so. This is bad for public health efforts, because when it happens to someone, unless they know how the flu and the vaccine work, they will be more likely to blame the vaccine or declare it doesn't work. In future seasons, they will be less likely, then, to get immunized.
With that in mind, what are public health departments to do? On the one hand, immunizing as many people as possible as quickly as possible can go a long way toward cutting this season's outbreaks short. On the other, there is a not insignificant risk that while we might greatly benefit this year, future outbreaks will be hampered due to people's erroneous perceptions of cause-and-effect.
It is a difficult question to answer. Personally, I think the best approach is to offer the vaccine, but education is absolutely vital. The Vaccine Information Sheet that providers are supposed to give patients along with the shot mention the 2-week latency for protection, but this isn't really emphasized. Given the current state of influenza outbreaks around the country, and with public health agencies pushing for expanded immunization clinics, that point cannot be stressed enough. If patient education is lacking, then health departments will be cutting themselves as they cut the epidemic.