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BART ROMBAUT AN. R. ACAD. NAC. FARM.

TABLE 1. Advantages and disadvantages of IPV and OPV

Advantage Disadventage

IPV

— killed? no mutation — parenteral administration
— heat-stable — expensive
— inactivation-procedure
— no vaccine-associated infections — no intestinal immunity

OPV

— cheap — mutation!
— oral administration — heat labile
— humoral and intestinal immunity — virus shedding
— vaccine-associated infections

There are also some disadvantages in using IPV: (1) unlike OPV,
IPV confers only very little immunity in the intestinal tract.
Consequently, in a person vaccinated with IPV, virulent virus can
still multiply inside the intestines and can be shed in stools. Hereby
risking continued circulation, (2) IPV is expensive. A higher dosis of
antigen is required (compared to OPV). There is the cost of the
syringe and moreover the need for trained health workers to
administer the vaccine using sterile procedures (13).

A few years after IPV, a live attenuated (weakened) oral polio
vaccine (OPV) became available. This vaccine was developed by
Dr. Albert Sabin. OPV is given orally (14, 15). This vaccine contains
attenuated or weakened virus from three different serotypes (the so-
called Sabin strains). This non-neurovirulent virus was also originally
grown on primary monkey kidney cells and after growth, the virus is
concentrated (and less purified than the IPV). The live virus of three
serotypes is then blended as follows: 106 TCID50 for type 1, 105 TCID50
for type 2 and 105.7 TCID50 for type 3. Each dose of OPV contains
residual amounts of antibiotics. Because OPV is very thermolabile,
stabilisers are added. This can be sucrose or MgCl2 (16).

The action of OPV is two-pronged : OPV induces antibodies in
the blood (serum immunity). Again, this will protect the individual
against polio paralysis by preventing the spread of poliovirus to the

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