MOI (Multiplicity of Infection) Calculator
Calculate the Multiplicity of Infection (MOI) or determine the required volume of viral stock needed for a target cell count.
Infection Parameters
Select calculation mode and enter host cell/viral stock values.
Actual MOI
- Uninfected (P₀): 36.8%
- Single virion (P₁): 36.8%
- Multi-infected (P₂₊): 26.4%
High vs. Low MOI Strategy
Use MOI $ge 5$ to ensure $> 99%$ of cells are transduced simultaneously. Use low MOI ($le 0.1$) for single-copy lentiviral integration screens.
Poisson Infection Probabilities by MOI Reference Table
| Multiplicity of Infection (MOI) | Uninfected P(0) | Exactly 1 Virion P(1) | Multiple Virions P(≥2) |
|---|---|---|---|
| MOI = 0.1 | 90.48% | 9.05% | 0.47% |
| MOI = 1.0 | 36.79% | 36.79% | 26.42% |
| MOI = 3.0 | 4.98% | 14.94% | 80.08% |
| MOI = 5.0 | 0.67% | 3.37% | 95.96% |
Methodology & Equations
MOI Equation
Calculates average number of plaque forming units (PFU) per host cell.
Poisson Stochastic Distribution
Determines exact proportion of cells infected by $k$ viral particles.
Frequently Asked Questions
What is Multiplicity of Infection (MOI)? ▼
MOI is the ratio of infectious agents (e.g., viral particles or bacteria) to target infection cells: $text{MOI} = {text{Total Virus Particles (PFU)}}{text{Total Host Cells}}$.
How does the Poisson distribution relate to MOI? ▼
Because viral entry into cells is a random stochastic process, the probability of a cell receiving $k$ virions follows a Poisson distribution: $P(k) = {e^{-text{MOI}} cdot text{MOI}^k}{k!}$.
Why do ~36.8% of cells remain uninfected at MOI = 1? ▼
At an average MOI of 1, $P(0) = e^{-1} approx 0.368$ (36.8%) of cells escape infection, while 36.8% receive exactly 1 virus and 26.4% receive multiple viruses.
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