Talk:Basic reproduction number

From Wikipedia, the free encyclopedia

some patent nonsense corrected: R0 is defined in the absence of internventions; R0 for SARS can't have been less than 1, otherwise epidemics would never have started (I think the *effective* or *net* repro number, Rt, is meant - would be worth mentioning that, but I haven't) Also R0>1 doesn't guarantee a major epidemic , it just makes it possible. We also need the word "mean".

This bit is also nonsense "If :R₀ = 1, then the infection will become endemic in the population." In reality R will never be 1, so it is irrelevant. In a stochastic model if R is one extinction will occur within a short time. Deterministic models are fine as approximations to stochstic models for large populations, but a population of 1 case is not large, and the deterministic result is irrelevant.

Also, remember this stuff applies equally to animals and plant, so I cut out words like "people".

Generally true that higher R0 makes control harder (though ohter factors come into play) and stuff about herd immunity threshold added.

Stuff on course of epidemics is irrelevant (why stop at SIR - what about SIS, SIRS etc. R0 applies to all).

Should we list sources for R0 estimates? If so, It's Mills, Nature 2004 for R0 for flu, Wallinga, Am J Epidemiol 2004 for SARS (though not strictly R0..more Rt). Anderson & May quote numbers for AIDS and mealses (though not sure if they are the same as those quoted. Generally people quote different values for subsaharan AFrica and elsewhere, adn of course wide variation possible in different groups - so best to say what population R0 is quoted for. Worth adding, maybe).

What about history? Shouldn't we mention history of R0? Kermack Mckendrick, Ross et al? And what about the Heesterbeck formulation for heterogeneous populations (the reason we need the word "typical"). Heesterbeck (who's PhD was titled R0) gives a great lecture including history of R0 (and the other names it's gone by, before Anderson & May popularized R0), and should probably mention his work here. All worth doing if anyone's got the time...

Other points: Why there is a separate definition for basic reproduction number and basic reproductive rate (http://en.wikipedia.org/wiki/Basic_reproductive_rate)? As far as I know they are just different names for the same concept. Now, if there is a difference between terms that I am not aware of, the reader can not tell by reading both articles. I agree that it would also be nice having a definition for Rt. That's my 2 cents anyway!

[edit] Uncertain reference

I doubt the reference cited for the reproduction range of HIV/AIDS as 2-5. The reference cited is from 1979, and transmission studies by Koopman and others were published at least 10 years later. 66.229.140.215 (talk) 13:35, 29 December 2007 (UTC)