Table 14.

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

Variant	Feature	Fully or partially vaccinated (n = 15,763)	Unvaccinated (n = 39,646)	Odds ratio	Chi-square p-value
Alpha	Acute upper respiratory infection	8	628	2.15	0.039
	Cough	37	2145	1.64	< 0.01
	Hypoxemia	33	770	0.61	< 0.01
	Pneumonia	68	3648	1.57	< 0.001
Delta	Acute pharyngitis	66	248	1.48	< 0.01
	Acute respiratory failure	122	577	1.94	< 0.001
	Hypoxemia	54	205	1.49	0.012
	Pneumonia	206	835	1.68	< 0.001
Omicron	Abnormal lung findings	168	127	0.63	< 0.001
	Acute pharyngitis	649	984	1.29	< 0.001
	Acute respiratory failure	360	604	1.43	< 0.001
	Acute upper respiratory infection	561	1176	1.83	< 0.001
	Disorder of nasal cavity	341	561	1.40	< 0.001
	Dyspnea	460	444	0.81	< 0.01
	Nasal congestion	173	266	1.30	< 0.01
	Pneumonia	581	891	1.31	< 0.001

p-value < 0.05 is significant.