JOURNAL OF THE NATIONAL MEDICAL ASSOCIATIONVOL. 104, NOS. 5 & 6, MAY/JUNE 2012 251
Evaluation of Serotype-Specific Immunity
to Streptococcus pneumoniae in Pregnant
Women and Cord Blood of Infants:
Impact of Race and Ethnicity
Shahana A. Choudhury, MD; Gwinnett Ladson, MD; Madina S. Kabir, MBBS
pneumoniae, the age of the patient, and race/ethnicity.1-5
Pneumococcus has 90 immunologically distinct capsular
polysaccharides.6 The most frequent serogroups/serotypes
for invasive diseases in children in the United States in the
pre-PCV7 era7 were 19, 6, 23, 14, 3, 9, 11, and 18. Seven
serogroups/serotypes (4, 6B, 9V , 14, 18C, 19F, and 23F)
accounted for more than 80% of invasive diseases in chil-
dren in the United States before introduction of PCV7 in
year 2000. All of these serogroups/serotypes are included
in PCV7, which now appears to be a less-than-optimal
vaccine in the United States or worldwide since the emer-
gence of nonvaccine serotypes,8 particularly 19A.
While immunization with PCV7 has significantly
reduced the incidence of invasive pneumococcal disease
(IPD) in children aged 5 years or less and adults aged 65
years or more (given the benefit of herd immunity),9 it
has also led to the emergence of nonvaccine serotypes
that are multidrug-resistant.8,10-12
Race and ethnicity may have an impact on the preva-
lence of specific serotypes causing disease. One recent
study determined that serotype 12F was more commonly
isolated from Melanesians and Tahitians/Wallisians than
Europeans.13 Similarly, investigators found that the risk of
IPD is 5 times greater in blacks who are positive for human
immunodeficiency virus (HIV) than in HIV-positive non-
blacks.14 According to a Centers for Disease Control 2010
report, the US incidence of IPD continues to be approxi-
mately 2-fold higher in blacks compared to whites (35.8
cases/100 000 in blacks vs 18.4 cases/100 000 cases in
whites) despite the introduction15 of PCV7 in year 2000. A
mong the risk factors for acquisition of inva-
sive and noninvasive pneumococcal disease
are inadequate serotype-specific immunity to S
Author Affiliations: Departments of Pediatrics (Dr Choudhury and Ms Kabir)
and Obstetrics and Gynecology (Dr Ladson), Meharry Medical College,
Correspondence: Shahana A. Choudhury, MD, Department of Pediatrics,
Meharry Medical College, 1005 D.B. Todd Blvd, Nashville, TN 37208
Funding/support: This project was supported by National
Institutes of Health grant S06 GM 08037-34S1.
Background: Although invasive pneumococcal disease
(IPD) has significantly decreased in children since the intro-
duction of the pneumococcal conjugate vaccine, instanc-
es of IPD from non-PCV7 serotypes have increased. Con-
cerns remain regarding the risk for IPD during the neonatal
period. Our objective was to measure quantitative antibody
levels to 16 serotypes of Streptococcus pneumoniae in
pregnant non-Hispanic black, non-Hispanic white, and His-
panic mothers, and in cord blood samples.
Methods: Antibody levels were evaluated by Luminex assay.
Results: Forty-two percent of all mothers had protective
(≥0.35 µg/mL) antibody levels to 16 serotypes. Hispanic
mothers were most likely to possess protective antibody lev-
els for 12 serotypes but were less likely to possess protective
antibody levels for serotypes 9V, 12F, and 18C, compared to
non-Hispanic white or black mothers. Thirty-three percent
of cord blood samples demonstrated protective antibody
levels. Hispanic infants had a higher prevalence of protec-
tive antibodies to all serotypes except 11A, 14, 18C, and 23F.
Non-Hispanic black infants had a higher prevalence of pro-
tective immunity to serotypes 11A, 14, and 18C, and non-
Hispanic white infants to only serotype 23F.
Conclusions: Hispanic mothers and their infants have a high-
er prevalence of protective immunity to most serotypes of S
pneumoniae, compared to white or black mothers/infants.
We found no evidence of a lower prevalence of protective
immunity to specific serotypes in non-Hispanic black vs non-
Hispanic white infants that might account for the reported
higher incidence of IPDs in blacks. Environmental factors in
Hispanic mothers may be responsible for their enhanced
level of immunity. A significant number of cord blood sam-
ples had inadequate levels of protective immunity to a vari-
ety of S pneumoniae serotypes.
Keywords: bacteria n antibody
J Natl Med Assoc. 2012;104:251-257
252 JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION VOL. 104, NOS. 5 & 6, MAY/JUNE 2012
PASSIVE IMMUNITIES TO S PNEuMONIAE
number of reasons have been suggested to account for the
higher risk in blacks (including blacks who are HIV-
positive), including a lower socioeconomic status, lack of
access to health care, immunization at a more advanced
stage of immunosuppression, a genetic susceptibility, or
the low use of vaccines in this population.16 There is also
suggestion that the serotypes responsible for pneumococ-
cal infection vary in whites vs blacks.2,16,17 Thus, black race
was suggested an independent risk factor for infection
with serotypes16,17 6A, 6B, 9N, 9V , 18C, 19A, 19F, and 23F.
An immune response to S pneumoniae is T-cell-
independent. Healthy infants in the first few months of
life are protected against S pneumoniae infections by
passive immunity from their mothers. The determinants
of this passive immunity include maternal immune sta-
tus and the level of passive immunity transferred from
mother to her infant. This passive immunity wanes soon
after birth, reaches a nadir at approximately 6 months of
life, and is replaced by antibodies made by the infant. A
recent study reported that an antibody level to S pneu-
moniae in the cord blood of at least 4.4 µg/mL is needed
if infants are to be protected up to 4 months of age.18
While some data are available regarding passive immu-
nities to S pneumoniae in cord blood of infants,18,19 no
data are available thus far analyzing passive immunities
from a racial/ethnic perspective. We therefore evaluated
and compared antibody levels in black, white (non-His-
panic), and Hispanic pregnant women and their babies.
The goal of this study was to determine if the higher
incidence of IPD in black infants was due to inadequate
levels of passive immunity antibodies to specific S pneu-
moniae serotypes. This goal was based on our hypothesis
that there is racial/ethnic disparity in some S pneumoniae
serotype-specific quantitative antibody levels in the United
States that may help explain the differences in prevalence
of IPD. Therefore, we compared S pneumoniae quantita-
tive antibody levels in non-Hispanic black, non-Hispanic
white, and Hispanic pregnant mothers and their infants,
broken down into specific serotypes. We choose to look at
Hispanics as a separate ethnic category, as Hispanic moth-
ers form a large part of our obstetric practice and little is
known about their comparative immunity.
In a preliminary study, we also found a significantly (p
= .03) higher total (23 serotype) of S pneumoniae antibody
levels in non-Hispanic black infants compared to the
non-Hispanic white infants despite adequate pneumococ-
cal vaccination coverage in all US racial/ethnic groups.
The protocol was reviewed and approved by the insti-
tutional review board at Meharry Medical College, and
informed written consents for mothers and babies were
obtained from all enrolled pregnant women.
sample size and power Calculation
The sample size calculation was based on earlier pre-
liminary data that included a total of 28 women (Table 1,
unpublished data) within an HIV-seronegative control
group (vs an HIV-seropositive study group) to compare
total (23 serotype) S pneumoniae antibody levels in the
mothers and cord blood of their infants. On further anal-
ysis of the antibody levels within the control subjects, a
remarkable difference (6.6-fold) was noted in the passive
cord blood antibody levels between African American
and non–African American (Hispanic and non-Hispanic
white) infants. Based on these preliminary data, we cal-
culated the necessary sample size for this study. Based
on these findings, a sample size of 75 in each group
would have 80% power to detect a difference of 225 in
the mean antibody levels to S pneumoniae (the difference
between a neonatal African American group mean of 40
and a non–African American control group mean of 265)
and a standard deviation of 481 using a 2-group t test
with a 2-sided significance level of .05. Therefore, we
adjusted the targeted enrollment goal per group to 80 to
account for a 10% dropout rate and loss to follow-up.
study population: pregnant Women
One hundred fifty-eight pregnant women were
enrolled in the study. Eighty-two were US-born and 76
were born outside of the United States (50 from Mexico;
15 from Honduras, Guatemala, and El-Salvador; and 11
from Nigeria). All of the Hispanic mothers had immi-
grated to the United States within the 10 years prior to
the initiation of the study. Seventy-two (46%), 21 (13%),
and 65 of 158 (41%) mothers were self-reported to be
non-Hispanic black, non-Hispanic white, and Hispanic,
respectively. Blood samples from pregnant mothers were
usually taken at the time of enrollment but always
table 1. Preliminary Studies: Racial/Ethnic Dependent Cord Blood Sample Totals for Preliminary
S pneumoniae Antibody Levelsa
Hispanic (n = 7)
Non-Hispanic (n = 12)
mean Antibody level µg/ml
(n = 19)
364.79 (± 780.42)
207.77 (± 219.28)
mean Antibody level µg/ml
(n = 9)
40.16 (± 34.72)
a Values are shown ±SD.
JOURNAL OF THE NATIONAL MEDICAL ASSOCIATIONVOL. 104, NOS. 5 & 6, MAY/JUNE 2012 253
PASSIVE IMMUNITIES TO S PNEuMONIAE
sometime before delivery. Cord blood samples were
available from 114 infants. Thirty-nine (34%) infants
were born to non-Hispanic black mothers, 11 (10%) to
non-Hispanic white mothers, and 64 (56%) to Hispanic
mothers. All cord blood samples had parallel mother
samples (mother-infant pairs). There were 3 pairs of
twins and all infants were born at term. Subjects were
either seen at a Meharry Medical College and/or the con-
tiguous Nashville General Hospital clinic, both of which
serve a low-income, largely minority population within
north Nashville. The mean (range) ages of pregnant
women at the time of serologic assays were 27 (19-37),
26 (16-42), and 31 (25-37) years for non-Hispanic black,
non-Hispanic white, and Hispanic women, respectively.
All relevant information about the subjects was
obtained from the subjects’ charts, including maternal
ages and gestational ages of the babies. Other informa-
tion regarding socioeconomic status, including educa-
tion level, number of household members, and income
level of the pregnant woman, was obtained from each
subject. None of the mothers in this study had previ-
ously received PCV7.
determination of Antibody levels
Aliquot serum and whole blood samples were stored
at –70ºC before shipping to an outside laboratory
(Neolab) for performance of antibody measurements for
16 serotypes (1, 2, 4, 5, 6B, 7F, 9N, 9V, 11A, 12F, 14,
15B, 18C, 19F, 23F, and 33F) of S pneumoniae, using a
previously described Luminex method.20 Inadvertently,
serotype 7F was assayed in mothers only, and 11A in
cord blood samples only.
The statistical analyses were performed using the
software program Intercooled Stata (version 8, StataCorp
LP, College Station, Texas). Continuous variables were
rounded to the nearest tenth and presented as mean ±
standard deviation; a p less than or equal to .05 was con-
• Antibody levels (serotype-specific) were
determined and compared between groups by
2-tailed t test.
• Paired mother-infant differences in mean
pneumococcal serotype-specific antibody levels
between groups were determined by Wilcoxon
signed rank test.
• Effect of confounding variables (socioeconomic
status, age of mother, gestational age of babies, and
number of pregnancies) on immune response was
done using analysis of variance with Bonferroni
table 3. Racial/Ethnic-Dependent Anti–S pneumoniae IgG Antibody Levels in All Mothers (n = 137)
mean (± sd)
hispanic (n = 65)
3.68 (± 8.37)
2.34 (± 5.74)
2.56 (± 6.26)
mean (± sd)
non-hispanic Black (n = 72)
1.09 (± 3.41)
0.73 (± 2.22)
0.50 (± 0.83)
a 2-Tailed t test.
table 2. Racial/Ethnic Disparities in Prevalence of S pneumoniae Serotype-Specific Protective Immunities
(≥0.35 µg/mL) in All Mothers (n = 158)
protective immunities, % protective immunities, %
(n = 21)
(n = 65)
(n = 72)
(n = 65)
Abbreviation: NS, not significant.
a 2-Tailed Fisher exact test.
254 JOURNAL OF THE NATIONAL MEDICAL ASSOCIATIONVOL. 104, NOS. 5 & 6, MAY/JUNE 2012
PASSIVE IMMUNITIES TO S PNEuMONIAE
correction, yielding a significance level of .01.
• Prevalence of serotype-specific protective immunity
(≥0.35 µg/mL) between groups of pregnant women
and their infants was performed by 2-tailed Fisher
in All mothers
All mothers possessed protective (≥0.35 µg/mL)
antibody levels to at least 1 serotype. A mean of 42%
(66 of 158) mothers had protective antibody levels to all
serotypes tested—the highest prevalence (54%) of pro-
tection was noted for serotype 14 and the lowest preva-
lence (20%) of protection was noted for serotype 4.
Only 8% mothers had antibody levels greater than or
equal to 4.4 µg/mL (level predicting protective passive
immunity at 4 months of age).
Stratification by race/ethnicity. No disparities were
observed in prevalence of protective (≥0.35 µg/mL)
immunities or quantitative antibody levels between non-
Hispanic black and white mothers. However, the preva-
lence of protective (≥0.35 µg/mL) immunities was sig-
nificantly higher in Hispanic mothers for serotypes 5,
6B, 7F, 9N, 15B, and 33F compared to both non-His-
panic black and white mothers; to serotypes 2, 4, 19F
and 23F when compared to non-Hispanic black mothers
only; and to serotype 1 when compared to non-Hispanic
white mothers only (Table 2). Hispanic mothers also had
significantly higher quantitative antibody levels to sero-
types 1, 9N, and 33F compared to non-Hispanic black
mothers (Table 3). There were no significant differences
in S pneumoniae serotype prevalences for non-Hispanic
black vs non-Hispanic white mothers, although the
actual prevalences of serotypes 1 and 5 in non-Hispanic
black mothers were double the prevalences seen in non-
Hispanic white mothers.
in All infants
All infants possessed protective (≥0.35 µg/mL) anti-
body levels to at least 1 serotype. A mean of 32% (37 of
114) cord blood samples demonstrated protective levels
of antibodies to all serotypes tested—the highest preva-
lence (59%) of protection was noted for serotype 11A
and the lowest prevalence (19%) of protection was noted
for serotype 4. Only 2% of infants had antibody levels
greater than or equal to 4.4 µg/mL (level predicting pro-
tective passive immunity at 4 months of age).
in mother-infant pairs
Fifty-three percent of Hispanic mothers had protec-
tive antibody levels to all serotypes tested vs 44% non-
Hispanic black and 35% non-Hispanic white mothers
(Tables 4 and 5). Hispanic mothers were most likely to
possess protective antibody levels for 12 serotypes and
table 4. Racial/Ethnic Disparities in Prevalence of S pneumoniae Serotype-Specific Protective Immunities
(PIs) (≥0.35 µg /mL) in Mother-Infant Pairs (n = 114)
(n = 11)
(n = 39)
(n = 64)
(n = 11)
(n = 39)
(n = 64)
Abbreviations: NA, not available; NH, non-Hispanic; NS, not significant.
a 2-Tailed Fisher exact test.
b Hispanic vs non-Hispanic white pairs.
c Non-Hispanic black vs non-Hispanic white pairs.
JOURNAL OF THE NATIONAL MEDICAL ASSOCIATIONVOL. 104, NOS. 5 & 6, MAY/JUNE 2012 255
PASSIVE IMMUNITIES TO S PNEuMONIAE
were less likely to possess protective antibody levels for
serotypes 9V, 12F, and 18C compared to either non-His-
panic white or black mothers.
Thirty-six percent of Hispanic infants had protective
antibody levels to all serotypes tested vs 29% of non-
Hispanic black and 24% of non-Hispanic white infants.
Hispanic infants were more likely to have protective
antibody levels to all serotypes except serotypes 11A,
14, 18C, and 23F; non-Hispanic black infants were more
likely to have protective antibody levels to serotypes
11A, 14, and 18C and non-Hispanic white infants to
only 1 serotype 23F compared to their counterparts.
No significant differences were found in quantitative
antibody levels or prevalence of protective (≥0.35 µg/
mL) immunities between non-Hispanic black and white
mothers. However, non-Hispanic black infants were
more likely to have significantly (p = .04) higher preva-
lence of protective passive immunity to serotype 11A
compared to the non-Hispanic white infants (Table 4).
Hispanic mothers had a significantly (p = .03) higher
prevalence of protective immunity to serotype 5 com-
pared to non-Hispanic white mothers. Serotype 9N was
close to being significant (Hispanic vs non-Hispanic
white mothers) (p = .06) (Table 4). Hispanic mothers
also had a higher antibody level to serotype 33F com-
pared to non-Hispanic black mothers, but the value did
not reach significance, with a p = .07 (Table 5). Hispanic
infants had significantly higher prevalence of protective
immunities to serotypes 1 (p = .03) and 15B (p = .02)
compared to non-Hispanic white infants (Table 4).
Hispanic infants were also more likely to have a signifi-
cantly (p = .01) higher quantitative antibody level to
serotype 19F compared to non-Hispanic black infants
and higher but insignificantly (p = .07 and p = .06,
respectively) to serotypes 9V and 15B compared to non-
Hispanic black and white infants, respectively (Table 5).
Socioeconomic status had no significant impact on
immune responses stratified by race or ethnicity.
Insignificant variability was noted in antibody levels in
the 3 sets of twins.
We examined antibody levels to 15 serotypes of S
pneumoniae in 158 pregnant women and 114 cord blood
samples. The intent was simply to determine the preva-
lence of serotype-specific protective immunity in moth-
ers from a low-income community and the level of pas-
sive immunity in their infants, with the assumption that
we would find a black:white disparity in 1 or more of
these serotypes to help account for the higher IPD in
blacks. Although, some data regarding passive immu-
nity to S pneumoniae in cord blood of infants are avail-
able in the literature,18,19 for the first time, we have also
analyzed data from a racial/ethnic perspective.
We found that only 42% of all mothers had protective
(≥0.35 µg/mL) levels of antibody to all 15 serotypes of S
pneumoniae. When stratified by mother’s place of birth,
Hispanic mothers and their infants were more likely to have
a higher prevalence of protective immunity to most sero-
types compared to their non-Hispanic white and black coun-
terparts. We found no evidence that low-income black
infants had a significantly lower prevalence of protective
passive immunity (≥0.35 µg/mL) to a specific serotype than
low-income non-Hispanic white infants. Lack of finding a
specific deficiency in blacks to account for the black:white
disparity most likely is due to a small sample size.
Since most of our Hispanic mothers were from
Mexico (77%), it is presumed that the higher levels of
table 5. Racial/Ethnic Dependent Anti-S pneumoniae IgG Antibody Levels in Mother-Infant Pairs (n = 114)
(n = 64)
non-hispanic Black pairs
(n = 39)
non-hispanic White pairs
(n = 11)
1.24 (± 2.25)
0.59 (± 1.18)
1.52 (± 3.06)
0.24 (± 0.42)
0.44 (± 0.67)
0.11 (± 0.15)
3.64 (± 10.14)
2.08 (± 5.41)
0.65 (± 1.94)
0.21 (± 0.21)
0.14 (± 0.24)
2.55 (± 3.78)
0.91 (± 1.34)
2.45 (± 6.71)
0.33 (± 0.61)
1.43 (± 2.95)
0.27 (± 0.38)
2.43 (± 6.22)
0.69 (± 1.29)
0.62 (± 0.80)
0.41 (± 0.78)
0.25 (± 0.26)
0.20 (± 0.25)
a 2-Tailed t test; p ≤ .05 considered significant.
b Hispanic vs non-Hispanic black pairs.
c Hispanic vs non-Hispanic white pairs.
256 JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION VOL. 104, NOS. 5 & 6, MAY/JUNE 2012
PASSIVE IMMUNITIES TO S PNEuMONIAE
immunity seen in this population may reflect the preva-
lent serotypes in Mexico and the ability of their immune
system to mount this level of immunity secondary to
environmental exposure and natural infection rather
than to vaccination (none of the mothers in this study
had been vaccinated). All Hispanic mothers in this study
had immigrated to the United States not more than 10
years before the initiation of this study.
Although there has been a significant US decline in
the incidence of IPD in children with the advent of
PCV7, along with an apparent elimination of the racial
disparity that had been previously reported,16 a recent
report from Massachusetts Department of Public Health
stated that of all serotypes isolated in children with IPD
(years 2001-2007), 85% were non-PCV7 and, further,
that Asians and Hispanics, in addition to blacks, were at
higher risk for contracting these infections than were
whites.21-24 The difference in incidence rates of IPD by
race/ethnicity also could not be attributed to differences
in vaccination coverage rates.25
According to Hsu et al,21 lack of functional activities
of antibodies elicited by PCV7 against 19A may in part
be responsible for the increase in incidence of IPD in
this population. Concerns remain towards a possible
genetic basis for increased susceptibility or reduced
immune responsiveness (functional) for specific sero-
types of S pneumoniae in different racial/ethnic groups.
Of the 16 serotypes studied, all 7 serotypes (4, 6B, 9V ,
14, 18C, 19F, and 23F) of PCV7 and 9 serotypes (1, 4, 5,
6B, 9V , 14, 18C, 19F, and 23F) of PCV13 were evaluated
in this study. Findings from our study suggest that Hispanic
and non-Hispanic black infants were more likely to have a
higher prevalence of protective passive immunity (~30%)
for the non-PCV7 and non-PCV13 serotypes compared to
21% of non-Hispanic white infants. All of these serotypes
are considered invasive, which should be a concern to
health care providers in the United States. In particular,
passive protective immunity levels for serotype 15B (non-
PCV7 and non-PCV13) were significantly (p = .02) higher
in Hispanic infants compared to the non-Hispanic white
infants. This finding may pose a risk for infection with this
nonvaccine serotype in vaccinated US non-Hispanic white
children under the age of 5 years through horizontal trans-
mission from their Hispanic counterparts.
According to researchers, a cord blood mean antibody
level of at least 4.4 µg/mL is required if infants are to be
protected up to 4 months of age (decay of passively
acquired antibodies).18 In our study, however, only 2% of
infants possessed this level of antibody in their cord
blood. This should remain a major concern with regards
to protecting neonates against IPD in the United States.
Boosting this passive immunity in neonates through
maternal immunization with pneumococcal polysaccha-
ride vaccine (PPV23) during the third trimester of preg-
nancy could maintain a protective antibody level for a
prolonged period. Nevertheless, timely vaccination with
conjugate pneumococcal vaccine (PCV13) first-dose
administration at 2 months of age should remain the most
important strategy to consider and reinforce at this time.
An evaluation of mother-infant paired data in this
study suggests that there may be racial/ethnic serotype
variability in transmission of passive antibodies from
mothers to their infants (Table 5). However, no straight-
forward correlation was noted in the antibody levels
between mothers and cord blood samples of their infants
based on serotype or race/ethnicity.
The study had a number of limitations. Although, our
preliminary data showed significant (p = .03) difference
in total (23 serotypes) antibody levels between non-His-
panic black and non-Hispanic white infants’ cord blood,
the current study did not show such differences to spe-
cific serotypes of S pneumoniae. Increasing the sample
size may show this difference. Unfortunately, immunity
to serotype 19A was not evaluated in this study due to
unavailability of this serotype in the assay panel used.
There was a significant discrepancy in the proportion of
available cord blood samples for Hispanic (98%) vs the
non-Hispanic white and black infants (~60%). This dis-
crepancy could have some impact on the disparities in
results seen in our study compared to national data on
the relative prevalence of IPD in infants from these pop-
ulation groups. Thus, the sample size may not have been
large enough to come to definite conclusions. However,
our study showed a poor correlation between protection
(as demonstrated by quantitative antibody levels ≥0.35
µg/mL) to specific serotypes of S pneumoniae in non-
Hispanic white, non-Hispanic black. and Hispanic
infants and the reported consistently higher rates of IPD
in black and Hispanic infants and children in the United
States despite adequate pneumococcal vaccination cov-
erage in all racial/ethnic groups. While a Luminex assay
quantitates the level of antibodies to specific S pneu-
moniae serotypes, it does not measure the functional
abilities of those antibodies. This would require an opso-
nophagocytic killing assay to determine opsonization
titers. Therefore, we recommend conducting future stud-
ies (using a larger number of subjects and including S
pneumoniae serotype 19A) to determine both functional
and quantitative levels of the specific serotypes of these
antibodies. These studies should also consider evaluat-
ing genetic factors in the immune pathway responsible
for reduced or enhanced immune responsiveness to spe-
cific serotypes of S pneumoniae in various racial and
We thank Peter F. Wright, MD; Diana Marver, PhD;
Barry Gray, MD; and Thomas A. LaVeist, PhD, for their
review of the manuscript.
JOURNAL OF THE NATIONAL MEDICAL ASSOCIATIONVOL. 104, NOS. 5 & 6, MAY/JUNE 2012 257
PASSIVE IMMUNITIES TO S pneumoniae
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