Разброс выделения вируса между пацентами-большой, несколько порядков, но на пике в мазках определялось от нескольких сотен тысяч до нескольких десятков миллионов "копий" вируса.
We observe that the virus load over time varies greatly across patients, some show long infection periods(20-25 days), others are short (∼10 days). The virus load function is able to describe the three phases of the virus for most of the patients (901, 902, 904, 908, and 930). In those patients, we observe the initial virus growth phase is rather quick and the virus reaches its carrying capacity within a day (a2−a1<1.08). The slope during the second phase varies from -0.13 to -0.57. The virus load reaches a saturation level, which is likely to be related to the innate immune response and it starts a phase of slow decay with a half-life time betweenT12= 1.22 and 5.33 days. After 15 days the virus load drops more quickly, possibly due to the adaptive immune response and at day 25 the virus is cleared.
nine monkeys showed only mild disease symptoms and they all fully recovered. Hence the infection cycle here is more indicative of a mild infection, in contrast to the human data considered above.
The characteristic values for the initial virus growth a 2<2.3 is common between all monkeys,indicating that the amount of initial viral dose is not so important. The virus load is biphasic in mostmonkeys (1-1, 1-2, 1-3, 2-2, 2-3, and 3-2) in which the rate of decay is larger (>0.6 days−1, and half-lifetime<1.2 days). For the remaining monkeys (2-1, 3-1, and 3-3) a fast decay phase is observed, following aslow decay with smaller decay rate. This distinction between biphasic and triphasic viral load suggests thatin some monkeys the action of the immune system is rather efficient.Compared to the human data we notice that the virus half-life times in Phase II isT12>1.2 days inboth human and monkeys experiencing all three phases, andT12<1.2 days in those which show a biphasicbehavior. Hence a biphasic behavior is indicative of faster virus clearance in Phase II. The length of the infection is estimated as about 27.5 days and for humans and 34 days for the monkeys, where the final decay phase starts significantly earlier in humansb1= 15 than in monkeysb1= 25−30. This could be an indication of a more efficient adaptive immune response in humans as compared to monkeys
We have shown that this virus load function can replicate observed virus load titers from Influenza A in mice and from SARS-CoV-2 in humans and in monkeys. A quick analysis shows already that macaque is agood model system for human infection. The early and intermediate infection phases are very similar, and the final elimination period is quicker in humans.