Scientists (Johnson and Eccles, 2005) provide evidence that cold exposure may induce cold symptoms without any contact to sick individuals. As we all carry dormant (sub-clinical) infections in our nose, genitals and other parts of the body, and these viruses may get reactivated. Ever noticed the need to blow nose after spending some time in cold air? Your body might be trying to expel the waking-up microbes.
Emerging health analysis software tools like Aurametrix aim at keeping us healthy by warning about symptoms and diseases. Prolonged exposure to cold means that 4-5 days after the exposure there is 10% probability of developing nasal stuffiness, sneezing, throat irritation of mild fever. 10% if Aurametrix knows nothing else about you. Higher if you are in the most vulnerable age & health conditions group, have a history of more frequent cold infections in prior years or were recently exposed to other stressors. Aurametrix can draw additional conclusions from looking at ingredients in your diet and chemicals in your environment. Medical records could add another thousand variables. Medical codes given to every documented complaint, prior medications, procedures, information about attending doctors and payments were shown to help predict C.difficile infections in hospitals using machine learning (Wiens, Guttag, Horvitz, 2012).
Social media (in addition to notifications by official sources) keeps us more aware and more afraid of the flu. But what if we are not able to keep away from exposure to a virus, forgot to clean our hands and could not avoid a non-ventilated area with sneezing sick people? The good news is that if we did everything else right we have a fighting chance. As it was shown in a scientific study (Huang et al., 2011), only 9 out of 17 healthy human volunteers exposed to H3N2 virus developed mild to severe symptoms.
So be happy to be healthy, in addition to doing your best to stay flu-free
Johnson C, & Eccles R (2005). Acute cooling of the feet and the onset of common cold symptoms. Family practice, 22 (6), 608-13 PMID: 16286463
Jankowski R, Philip G, Togias A, Naclerio R. Demonstration of bilateral cholinergic secretory response after unilateral nasal cold, dry air challenge. Rhinology 1993; 31: 97-100
J. Wiens, J. Guttag, E. Horvitz. Learning Evolving Patient Risk Processes for C. Diff Colonization, Machine Learning for Clinical Data Analysis, ICML 2012, Edinburgh, Scotland, June 2012.
Huang Y, Zaas AK, Rao A, Dobigeon N, Woolf PJ, Veldman T, Øien NC, McClain MT, Varkey JB, Nicholson B, Carin L, Kingsmore S, Woods CW, Ginsburg GS, & Hero AO 3rd (2011). Temporal dynamics of host molecular responses differentiate symptomatic and asymptomatic influenza a infection. PLoS genetics, 7 (8) PMID: 21901105
Worst of flu season may be over. But you can still catch a chill. If you shake hands with lots of sick people, for example. Or don't keep sufficiently warm. Yes, your mother has told you, and you thought it was just an old wives' tale, but it wasn't.