TABLE 3.

Contacts showing immune marker(s) of potential infection

Age (yr)	Vaccination status	Convalescent-period sample value/1-yr sample valuea					Exposure	Symptoms
		Serology		OPX-specific T cell		OPX-specific B cell
		IgM	IgG	CD4	CD8
12	No	−/NS	+/NS	−/NS	−/NS	NS/NS	Direct contact with prairie dog	None reported
13	No	−/NS	+/NS	−/NS	−/NS	NS/NS	Direct contact with prairie dog	None reported
35	No	−/−	−/+	NS/NS	NS/NS	NS/+	Indirect contact with prairie dog	None reported
37	Yes	−/−	−/+	+/+	−/+	−/+	Indirect contact with prairie dog	None reported
39	Yes	−/−	+/+	−/+	−/−	−/−	Direct contact with prairie dog	Fever, rash,e lymphadenopathy, headache
42	Yes	−/−	+/+	NS/NS	NS/NS	+/−	No contact with prairie dog (only with human case)	None reported
42	Yes	−/eqb	+(1.26)/+(0.274),c 4.6× drop	NS/NS	NS/NS	NS/−	Direct contact with prairie dog	Rash,e cough, sore throat, sweats, headache
46	Yes	−/−	+/NS	−/−	−/−	+(0.262)/+(0.02),d 13× drop	No contact with prairie dog (only with human case)	None reported
49	Yes	+/+	+/+	NS/NS	NS/NS	NS/+	Indirect contact with prairie dog	Fever, sore throat, sweats, chills, malaise, headache, diarrhea, myalgia, backache
56	Yes	−/−	+/+	−/−	−/+	+/NS	Indirect contact with prairie dog	None reported (multiple previous vaccinations for smallpox)
60	Yes	−/+	+/+	NS/NS	NS/NS	NS/−	Direct contact with prairie dog	None reported

^a+, positive; −, negative; NS, no sample submitted.

^beq, equivocal result.

^cNumerical values are ODs at 450 nm.

^dNumerical values are the average OPX-specific IgG production B-cell spot divided by the total IgG spot count (all IgG-producing cells), equaling the frequency.

^eRash was reported; absence of fever and/or negative laboratory findings (PCR/culture/IgM) prevented a case classification.