calculating the reproductive ratio. reproductive ratio, r 0 the average number of new infections we...
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Calculating the Calculating the Reproductive Reproductive RatioRatio
Reproductive Reproductive Ratio, RRatio, R00
• The average number of new infections we expect to see for each infected person in the epidemic.
• For Standing Disease, R0 is 2
Step 0 1 2 3 4 5 6 7
No. new infection
s1 2 4 8 16 32 64 128
Counter Counter PlaguePlague11stst scenario scenario
No. on die
No. of new infections
1 0
2 0
3 1
4 1
5 2
6 3
What is the average number of new infections we expect to see for each infected person?•Use the probability of each outcome to calculate R0 for this scenario.
Counter Counter PlaguePlague11stst scenario scenario No.
on die
No. of new
infections
Av. no. new
infections
expected
1 0 0
2 0 0
3 1
4 1
5 2
6 3
What is the average number of new infections we expect to see for each infected person?•Use the probability of each outcome to calculate R0 for this scenario.
R0 =
1
61
62
63
6
7
6
Counter Counter PlaguePlague22ndnd scenario scenario
No. on die
No. of new infections
1 0
2 0
3 1
4 1
5 1
6 2
What is the average number of new infections we expect to see for each infected person?•Use the probability of each outcome to calculate R0 for this scenario.
Counter Counter PlaguePlague22ndnd scenario scenario No.
on die
No. of new
infections
Av. no. new
infections
expected
1 0 0
2 0 0
3 1
4 1
5 1
6 2
What is the average number of new infections we expect to see for each infected person?•Use the probability of each outcome to calculate R0 for this scenario.
R0 =
1
61
61
62
6
5
6
Counter Counter PlaguePlague
No. on die
No. of new
infections
Av. no. new
infections
expected
1 ? ?
2 ? ?
3 ? ?
4 ? ?
5 ? ?
6 ? ?
How could you set up Counter Plague so that R0 equals:
1.54
•What is the largest value of R0 you can get in Counter Plague?
2
3