IMMUNITY IN VULNERABLE
GROUP(NEONATES & ELDERLY)
Assist Prof Dr.
Syed Yousaf Kazmi
OBJECTIVES
• Discuss the immune status of neonates &
elderly
• Identify the common infections in these two
age groups
• Describe some of the preventive strategies
IMMUNE STATUS IN NEONATES AND
ELDERLY-GENERAL INTRO
• Immune system is immature in
neonates while it has waned in
elderly
• Both extremes of life are susceptible
to infections
• Elders have increase incidence of
autoimmune disease, cancers and
tolerance to transplants
• Fetus lived in sterile environment-no
past exposure to pathogen, no
memory cells; face challenge
• The neonate immune system is
diminished in quantity & quality
IMMUNE STATUS NEONATEINNATE ARM
• Physical barriers are immature
e.g. thin skin, low sebum
production etc.
• No microbial flora to guard
against pathogens
• Short length & small diameter of
respiratory tree-easy access of
pathogens
• Plugging of respiratory tree by
mucus-trap pathogens
• Cough & sneeze reflex
• Acid pH
IMMUNE STATUS NEONATEINNATE ARM
• Neutrophils , Macrophage,
Monocytes have reduced
functions in neonates
• Chemotaxis-reduced
• Neutrophils L-selectins reduced in
number
• ↓ Phagocytosis, Opsonization
• ↓ complement (C9) predisposes
to E. coli infection
• Macrophage response to IFN-  by
activated T-helper cells is
reduced-intracellular pathogens
killing ↓
IMMUNE STATUS NEONATEADAPTIVE ARM
• Humoral response in neonate is
decreased
• Secretion of cytokines decreased
e.g. IL-4, IL-10 etc.
• IgG and IgA responses to
pathogens, although inducible, are
relatively weak
• Neonate is almost wholly
dependent upon passive transfer
of Immunoglobulin from mother
IMMUNE STATUS NEONATEADAPTIVE ARM
• During intrauterine life, tolerance
to fetal allo-antigens due to
immune hypo-responsiveness
• Fetal immune system is directed
to TH2 arm than TH1 (protect
against placental & fetal damage)
• Suppression of TH1 arm of
immune system continues in
neonate period
• Cytotoxic T cell functions are
diminished esp against viruses
(e.g. RSV) than adult children
INFECTIONS IN NEONATES
NEONATAL SEPSIS
 Group B streptococci
 Escherichia coli
 Listeria monocytogenes
 Respiratory syncytial virus
(RSV)




Herpes simplex virus (HSV)
Cytomegalovirus (CMV)
Varicella-zoster virus (VZV)
Candida species
INTRAUTERINE INFECTIONS
Toxoplasma gondii
Others (Syphilis)
Rubella
Cytomegalovirus
Herpes simplex virus
NEONATAL CONJUNCTIVITIS
Staph aureus
UMBILICAL SEPSIS (OMPHALITIS)
COMMUNITY ACQUIRED(3-6 wks)
Streptococcus pneumoniae
Streptococcus pyogenes
AGE RELATED CHANGES IN ELDERLY
• Poor cough/ sneeze reflex
• Stiff respiratory cage
• Poor mucociliary function
• Prostate hypertrophy-urine
stagnation
• Replacement of red marrow
with fat
• Deteriorating function of
multiple organs e.g. kidney, liver
• Poor blood supply to peripheral
tissue
SHIFT OF IMMUNE STATUS IN ELDERLY
• Decrease number of HLA class I and
II antigenic sites on lymphocytes
• Decreased proportion of T, B, cells
• NK cells increased density per cell
• Decreased number of monocytes
• Decreased ability of dendritic cells
to stimulate T-cell secretion of IFN and IL2
• Functional impairment of
macrophages and granulocytes
• Macrophages produce less IFN-
IMMUNE STATUS OF ELDERLY
B-CELLS FUNCTION
• Decreased number of circulating
and peripheral blood B cells
• Decreased generation of primary
and secondary memory B cells
• General decline in lymphoproliferative capacity
• General decrease in humoral
responsiveness:
• Decline in high affinity protective
antibody production of
Germinal center-site of B lymphocytes production
IMMUNE STATUS OF ELDERLY
T-CELLS FUNCTION
• General decline in cell mediated
immunity
• T-cell population become
hyporesponsive
• Decline in new T-cell production
• Increase in proportion of memory
T-cells
• Decrease in new T-cells
production
• Diminished functional capacity of
new T-cells
T cytotoxic cells attacking cancer cell
INFECTIONS IN ELDERLY
Increased incidence of following
infections occur in elderly
• E. Coli
• Streptococcus pneumonia
• Mycobacterium tuberculosis
• Pseudomonas aeruginosa
• Herpes virus
• Influenza virus pneumonia
• Reappearance of latent viral
infections e.g. Varicella zoster
PREVENTION OF INFECTIONS IN
NEONATES & ELDERLY
CARE OF NEONATES (DELIVERY)
Deliveries carried out by expert midwives
Observation of hand hygiene
Observation of universal precautions/ barrier nursing
Use of clean sterilized equipments in hospital/ labor rooms etc.
ELDERLY PERSONS
Geriatric care
Care of old age related diseases
Pharmacological management of old age diseases like BPH, DM
etc.
PREVENTION OF INFECTIONS IN NEONATES
& ELDERLY
IMMUNIZATION
Follow EPI program of the country
Old age specific immunization e.g. pneumovax, Influenza virus,
etc.
MANAGEMENT OF INFECTION
Prompt identification of pathogen & appropriate treatment
Use of microbiological lab (C/S testing etc.)
INFRASTRUCTURE & TRAINING
Strengthen public health infrastructures to support surveillance,
response, and research to implement prevention and control of
infections