Influenza epidemics occur every year, most commonly in January-February in Newfoundland and last about 8 weeks with a very noticeable peak for about 2-3 weeks starting about the 3rd or 4th week. The current H1N1 influenza pandemic has markedly focused attention on the spectrum of illness associated with influenza. While it is true that this epidemic is relatively large and associated with relatively more illness requiring hospitalization than recent seasonal epidemics, it has not been catastrophic and is comparable to other bad seasonal influenza epidemics in many respects.
Influenza is certainly associated with deterioration of respiratory function in people with underlying respiratory disease and consultations and admissions for COPD, asthma and pneumonia markedly rise during epidemic peaks. Oseltamivir is a generally non-toxic, effective therapy for influenza. This gives rise to obvious primary care provider questions.
Should patients that do not need hospital referral be tested and/or treated for influenza during influenza epidemics?
Tested - No in general. Testing is not timely enough to help with treatment decisions. Improvements in point-of-care tests may change this in future.
Treated - Yes in general. Especially if the illness has been present for less than 2 days as neuraminidase inhibitor effect is greatest if initiated early. Oseltamivir 75 mg BID x 5 days is the standard course with some advocating a 10 day course for overtly immunocompromised patients.
Should COPD and Asthma patients receive antibacterial antibiotics as well?
This is a harder question. I am generally in favour of a conservative approach to antibiotics and most exacerbations of COPD and virtually all exacerbations of asthma are appropriately treated without antibacterial antibiotics. I definitely advise a higher threshold for antibacterials than for antivirals during peak influenza season. Patients who are felt to have pneumonia should, of course, be treated.
If I do treat with an antibacterial, which one?
Doxycycline is an underused, effective, inexpensive option. Perhaps because it has fallen out of favour for many years, resistance among respiratory pathogens is very low in contrast to the macrolides (erythromycin, clarithromycin and azithromycin) where Streptococcus pneumoniae resistance is above 25% in Newfoundland. Amoxicillin/clavulanate is a good second-line choice while I would reserve fluoroquinolones (moxifloxacin, levofloxacin) for failures.