Table 3.

Weighted average computations for the basic reproduction number and vaccine effectiveness values when the proportion of infections caused by Omicron (Delta) is ${\omega }_0$ ($1-{\omega }_0$).

	Group	Omicron	Delta	Weighted average formula	${\omega }_O=50\%$ case
Basic reproduction number (R0), $k\in \{u,v,b\}$	Students	$3\times 6=18$	6	$R{0}_{(k,s)}^{{\omega }_O}=6\times (1-{\omega }_O)+18\times {\omega }_O$	$R{0}_{(k,s)}^{{\omega }_O=50\%}=12$
	Faculty	$3\times 3.2=9.6$	3.2	$R{0}_{(k,f)}^{{\omega }_O}=3.2\times (1-{\omega }_O)+9.6\times {\omega }_O$	$R{0}_{(k,f)}^{{\omega }_O=50\%}=6.4$
Vaccine effectiveness against infection ($\epsilon$)	Vaccinated	33%	80%	${\epsilon }_v^{{\omega }_O}=80\%\times (1-{\omega }_O)+33\%\times {\omega }_O$	${\epsilon }_v^{{\omega }_O=50\%}=56.5\%$
	Boosted	69.4%	86.7%	${\epsilon }_b^{{\omega }_O}=86.7\%\times (1-{\omega }_O)+69.4\%\times {\omega }_O$	${\epsilon }_b^{{\omega }_O=50\%}=78.05\%$
Vaccine effectiveness against hospitalization ($\upsilon$)	Vaccinated	70%	91.7%	${\upsilon }_v^{{\omega }_O}=91.7\%\times (1-{\omega }_O)+70\%\times {\omega }_O$	${\upsilon }_v^{{\omega }_O=50\%}=80.85\%$
	Boosted	93%	97.5%	${\upsilon }_b^{{\omega }_O}=97.5\%\times (1-{\omega }_O)+93\%\times {\omega }_O$	${\upsilon }_b^{{\omega }_O=50\%}=95.25\%$