Number of newly infected patients
Timing of booster doses: Comparison of 3 methods of vaccination for any citizen;
(1)When immunity acquired by the 2nd dose is lost and infection is possible (assuming doctor's judgment)
(2)180 days (about 6 months) after the 2nd dose
(3)240 days (about 8 months) after the 2nd dose
Regarding vaccine passport:
(a)Vaccine passport not introduced
(b)Introduced: Holders come and go freely, and non-holders have only 30% less contact with people than holders
(c)Introduced: Holders come and go freely, and non-holders have 50% less contact with people than holders
Other settings: State of emergency ~9/30, vaccine effect on infection prevention 1st 70%, 2nd 95%; on serious illness prevention 1st 68%, 2nd 98%. After 2nd, the effect peaks at 1-2w and decreases the effect on infection prevention at 1/200 (1/500 in the case of natural infection)/day
Number of seriously ill patients
Timing of booster doses: Comparison of 3 methods of vaccination for any citizen;
(1)When immunity acquired by the 2nd dose is lost and infection is possible (assuming doctor's judgment)
(2)180 days (about 6 months) after the 2nd dose
(3)240 days (about 8 months) after the 2nd dose
Regarding vaccine passport:
(a)Vaccine passport not introduced
(b)Introduced: Holders come and go freely, and non-holders have only 30% less contact with people than holders
(c)Introduced: Holders come and go freely, and non-holders have 50% less contact with people than holders
Other settings: State of emergency ~9/30, vaccine effect on infection prevention 1st 70%, 2nd 95%; on serious illness prevention 1st 68%, 2nd 98%. After 2nd, the effect peaks at 1-2w and decreases the effect on infection prevention at 1/200 (1/500 in the case of natural infection)/day
Insights
・Vaccinating 6 months after the 2nd dose is safer than delaying until 8 months after. In both cases, however, a new wave of new infections will begin in the fall of 2021 and early 2022, reaching a substantial figure in Februaryc Therefore, 8 months after the 2nd dose (MHLW draft on 9/17), there are concerns about a large wave in the number of infected & seriously ill patients even with the introduction of the vaccine passport
・It is difficult to assume that the number of people in Tokyo alone will exceed 1,000 again at this stage and stay below 10,000 at the maximum (the calculation showed more than 100,000 people in Tokyo per day, but the reliability of the maximum value at this volume is low because it is a nonlinear phenomenon).
・We were able to verify once again that the effect of vaccination, in which doctors judge each individual and monitor the decline of antibodies (*), is significant. In the case of (1), there will be no 6th wave that exceeds the 5th wave.
・If more people accept the vaccine passport, the effect of (1) will be even greater, but the difference is small compared to the effect of "doctors’ judgment for each individual"
* Published on 9/13: At clinics, "it is possible to determine the need for booster doses, not by directly looking at antibody titers, but by judging with the available information such as medical history and use of immunosuppressive drugs" (Dr. Morihito Takita, Navitas Clinic, etc.). However, separate operations are required for large-scale vaccination sites
