TABLE 3.

Number needed to treat (NNT) and cost‐effectiveness for prevention of COVID‐19 deaths by an extra vaccine booster against SARS‐CoV‐2 using infection fatality rates from Denmark from 2022 and hypothetical vaccine efficacies and vaccine costs (per dose) and assuming all people are eventually infected.

Age group (in years)	Relative vaccine efficacies for the prevention of COVID‐19 deaths
	10%	30%	50%	80%	90%	95%	99%
Number needed to treat to prevent one COVID‐19 death
17–35	625,000	208,333	125,000	78,125	69,444	65,789	63,131
36–50	243,902	81,301	48,780	30,488	27,100	25,674	24,637
51–60	131,579	43,860	26,316	16,447	14,620	13,850	13,291
61–72	66,225	22,075	13,245	8278	7358	6971	6689
Costs to prevent one COVID‐19 death assuming vaccine costs of 5 US Dollars
17–35	3,125,000	1,041,665	625,000	390,625	347,220	328,945	315,655
36–50	1,219,510	406,505	243,900	152,440	135,500	128,370	123,185
51–60	657,895	219,300	131,580	82,235	73,100	69,250	66,455
61–72	331,125	110,375	66,225	41,390	36,790	34,855	33,445
Costs to prevent one COVID‐19 death assuming vaccine costs of 20 US Dollars
17–35	12,500,000	4,166,660	2,500,000	1,562,500	1,388,880	1,315,780	1,262,620
36–50	4,878,040	1,626,020	975,600	609,760	542,000	513,480	492,740
51–60	2,631,580	877,200	526,320	328,940	292,400	277,000	265,820
61–72	1,324,500	441,500	264,900	165,560	147,160	139,420	133,780
Costs to prevent one COVID‐19 death assuming vaccine costs of 120 US Dollars
17–35	75,000,000	24,999,960	15,000,000	9,375,000	8,333,280	7,894,680	7,575,720
36–50	29,268,240	9,756,120	5,853,600	3,658,560	3,252,000	3,080,880	2,956,440
51–60	15,789,480	5,263,200	3,157,920	1,973,640	1,754,400	1,662,000	1,594,920
61–72	7,947,000	2,649,000	1,589,400	993,360	882,960	836,520	802,680