. 2022 Mar 9;94(7):2939–2961. doi: 10.1002/jmv.27688

Table 1.

Declining humoral response post second dose administration of SARS‐CoV‐2 mRNA vaccine

Author	Vaccine	Country of origin	Sample size	Mean/median age	Immunoglobulin measurement	Serial/nonserial serologic measurement	Reported values	% Difference from peak
Campo et al ¹⁰	Pfizer‐BioNTech	Italy	Healthcare workers: 274	Median (range)	Diasorin, LIAISON, IgG, S1/S2	Serial	Geometric means and 95% confidence Intervals	D28
			Healthcare workers: 274	Median (range)				There is 9% decrease 21 days after the peak rise of IgG titer on Day 7 after full vaccinationD61There is 41% decrease 54 days after the peak rise of IgG titer on Day 7 after full vaccination
			Male: 99	46.1 years				D147
			Female: 175	(23–69 years)				There is 55% decrease 140 days after the peak rise of IgG titer on Day 7 after full vaccination
Salvagno et al. ¹²	Pfizer‐BioNTech	Italy	Healthcare workers: 787	Mean age: 44 ± 12 years	Roche, Elecsys, total Ig, RBD	Serial	Medians and interquartile ranges	D90
			<65 years: 754					There is 38% decrease 60 days after the peak rise of IgG titer on Day 30 after full vaccination
			≥65 years: 33					D180
			Male: 268					There is 55% decrease 150 days after the peak rise of IgG titer on Day 30 after full vaccination
			Female: 519
Ponticelli et al. ¹⁷	Pfizer‐BioNTech	Italy	Healthcare workers: 162	Mean age: 42.5 ± 11.9 years	SNIBE, MAGLUMI, IgG, RBD	Serial	Medians and interquartile ranges	D180
			Male: 68					D180
			Female: 94					There is 90% decrease 150 days after the peak rise of IgG titer on Day 30 after full vaccination
Salvagno et al. ¹⁸	Pfizer‐BioNTech	Italy	Baseline SARS‐CoV‐2	Median age: 42 years	Euroimmun, IgA, spike S1 subunit	Serial	Medians and interquartile ranges	D180
			Seronegative	Median age: 42 years				D180
			Healthcare workers: 97	IQR: 31–52 years				There is 71% decrease 150 days after the peak rise of IgA titer on Day 30 after full vaccination
Kato et al. ¹⁹	Pfizer‐BioNTech	Japan	Healthcare workers: 98	Median age: 43 years	Tosoh, AIA‐CL, IgG, nucleocapsid/spike	Serial	Geometric means and 95% confidence intervals	D201
			Male: 24	IQR: 38–49 years				D201
			Female: 74	IQR: 38–49 years				There is 93% decrease 180 days after the peak rise of IgG titer on Day 21 after full vaccination
Naaber et al. ²⁰	Pfizer‐BioNTech	Estonia	Laboratory employees: 122	Median age: 34 years	Abbott, IgG, RBD	Serial	Medians and interquartile ranges	D42
								There is 48% decrease 35 days after the peak rise of IgG titer on Day 7 after full vaccination
								D84
								There is 79% decrease 87 days after the peak rise of IgG titer on Day 7 after full vaccination
			Male: 21	Range: 21–69 years				D180
			Female: 101	Range: 21–69 years				There is 94% decrease 161 days after the peak rise of IgG titer on Day 7 after full vaccination
Laing et al. ²¹	Pfizer‐BioNTech	USA	Healthcare workers: 187	Mean age: 42.8 years	LakePharma, Multiplex microsphere‐based immunoassay, IgG, nucleocapsid/spike	Serial	Geometric meansand 95% confidence intervals	D180
			Male: 56	IQR: 21–69 years				D180
			Female: 131	IQR: 21–69 years				There is 77% decrease 150 days after the peak rise of IgG titer on Day 30 after full vaccination
Israel et al. ²²	Pfizer‐BioNTech	Israel	2653	Mean age: 56.45 ± 15.87 years	Abbott, Alinity i, IgG, RBD	Nonserial	Medians and interquartile ranges	D30–59
								There is 48% decrease 30 days after the peak rise of total antibody titer on Days 0–29 after full vaccination
								D60–89
								There is 78% decrease 60 days after the peak rise of total antibody titer on Days 0–29 after full vaccination
								D90–119
								There is 87% decrease 90 days after the peak rise of total antibody titer on Days 0–29 after full vaccination
								D120–149
								There is 89% decrease 120 days after the peak rise of total antibody titer on Days 0–29 after full vaccination
								D150–179
								There is 92% decrease 150 days after the peak rise of total antibody titer on Days 0–29 after full vaccination
								D180+
								There is 95% decrease 180 days after the peak rise of total antibody titer on Days 0–29 after full vaccination
Kertes et al. ²³	Pfizer‐BioNTech	Israel	8395	No data	Abbott, Quant II,IgG, RBD	Nonserial	Means and 95% confidence intervals	D30–59
								There is 42% decrease 30 days after the peak rise of total antibody titer on Days 7–29 after full vaccination
								D60–89
								There is 78% decrease 60 days after the peak rise of total antibody titer on Days 7–29 after full vaccination
								D90–119
								There is 87% decrease 90 days after the peak rise of total antibody titer on Days 7–29 after full vaccination
								D120–149
								There is 89% decrease 120 days after the peak rise of total antibody titer on Days 7–29 after full vaccination
								D150–179
								There is 92% decrease 150 days after the peak rise of total antibody titer on Days 7–29 after full vaccination
								D 180+
								There is 95% decrease 180 days after the peak rise of total antibody titer on Days 7–29 after full vaccination
Salvagno et al. ²⁴	Pfizer‐BioNTech	Italy	86	Median age: 45 years	DiaSorin, LIAISON, IgG, spike trimeric	Serial	Medians and interquartile ranges	D180
Salvagno et al. ²⁴	Pfizer‐BioNTech	Italy	86	IQR: 31–53 years	New Industries Biomedical Engineering Co., LTD, MAGLUMI, IgG, RBD	Serial	Medians and interquartile ranges	There is 83% and 92% decrease 150 days afterthe peak rise of anti‐spike trimeric IgG and RBD IgG titers, respectively, on Day 30 after full vaccination
Khoury et al. ²⁵	Pfizer‐BioNTech	Israel	Healthcare workers: 100	Mean age:	Abbot's © quant assay, IgG, RBD	Serial	Medians	D60
							and ranges	There is 56% decrease 30 days after the peak rise of total antibody titer on Day 30 after full vaccination
								D90
			Male: 55					D90
			Female: 45					There is 88% decrease 60 days after the peak rise of total antibody titer on Day 30 after full vaccination
				40.7 ± 13.7 years
								D120
								There is 94% decrease 90 days after the peak rise of total antibody titer on Day 30 after full vaccination
Ciabattini et al. ²⁶	Pfizer‐BioNTech	Italy	145	Mean age: 48.8 ± 14.3 years	In‐house ELISA, IgG, S1/S2	Nonserial	Geometric means and 95% confidence Intervals	D97
								There is 65% decrease 90 days after the peak rise of anti‐spike IgG titer on Day 7 after full vaccination
								D167
								There is 85% decrease 160 days after the peak rise of anti‐spike IgG titer on Day 7 after full vaccination
Brisotto et al. ²⁷	Pfizer‐BioNTech & Moderna	Italy	516	Median age: 46.5 years	SNIBE, MAGLUMI, IgG, RBD	Serial	Medians and interquartile ranges	D20
			Male: 145	IQR: 36–55 years				D20
			Female: 371	IQR: 36–55 years				There is 83% decrease 90 days after the peak rise of IgG titer on Day 30 after full vaccination

Abbreviations: IgG, immunoglobulin G; mRNA, messenger RNA; RBD, receptor‐binding domain; SARS‐CoV‐2, severe acute respiratory syndrome coronavirus 2.