Table 13.

Chi-square tests comparing feature significance in partially vaccinated versus unvaccinated individuals across the Alpha, Delta and Omicron waves.

Variant	Feature	Partially vaccinated (n = 4207)	Unvaccinated (n = 39,646)	Odds ratio	Chi-square p-value
Alpha	Cough	31	2145	1.52	0.031
	Hypoxemia	27	770	0.58	< 0.01
	Pneumonia	56	3648	1.48	< 0.01
Delta	Acute respiratory failure	34	577	1.67	< 0.01
	Pneumonia	45	835	1.89	< 0.001
Omicron	Abnormal lung findings	40	127	0.68	0.04
	Acute pharyngitis	141	984	1.53	< 0.001
	Acute respiratory failure	73	604	1.802	< 0.001
	Acute upper respiratory infection	116	1176	2.26	< 0.001
	Disorder of nasal cavity	71	561	1.717	< 0.001
	Hypoxemia	19	234	2.66	< 0.001
	Nasal congestion	28	266	2.05	< 0.001
	Pneumonia	129	891	1.51	< 0.001

p-value < 0.05 is significant.