Weniger BG, Papania MJ.
Alternative Vaccine
Delivery Methods
[Chapter 61].
Web
http://bit.ly/Vaccines6thChap61a
Page
1219
Safety of
multiuse-nozzle jet
injectors (MUNJIs)
Beginning in the
1960s, concerns arose
for potential iatrogenic
transmission of
bloodborne pathogens by
MUNJIs, which use the
same nozzle to inject
consecutive patients
without intervening
sterilization. 688 , 693
, 694 , 699 Unpublished
bench and chimpanzee
studies indicated
hepatitis B
contamination could
occur because blood or
HBsAg remained in nozzle
orifices despite
recommended alcohol
swabbing between
injections. 700 , 701
Others, however,
reported negative
results in bench or
animal testing when they
tried to detect
contamination, 529 , 564
, 702 , 703 or they
pointed to the lack of
epidemiologic evidence
of a problem. 551 , 702
, 704 , 705 Then in
1985, Brink and
colleagues described a
careful animal model in
which a Med-E-Jet
transmitted lactate
dehydrogenase elevating
virus (LDV) between mice
in 16 (33%) of 49
animals. 706
A few months later, fact
superseded theory when a
Med-E-Jet caused an
outbreak of several
dozen cases of hepatitis
B among patients in a
California clinic.
707–709 Subsequent
clinical, 710 field, 711
, 712 bench, 713 animal,
714 , 715 and
epidemiologic, 716 , 717
studies added more
evidence that MUNJIs
could transmit pathogens
between patients. This
led to warnings and
discontinuation of their
use by public health
authorities, 718 , 719
and to market withdrawal
of the Ped-O-Jet and
discontinuation of its
US military use in 1997.
497 , 720
In the mid 2000s, a
MUNJI was reengineered
with disposable caps to
try to prevent
contaminating blood or
tissue fluid from
splashing back onto the
reusable nozzle,
potentially to infect
the next patient. 721
The cap contained three
plastic washers with
axially aligned central
holes of about 1 mm in
diameter for the jet
stream to pass in one
direction along the
centimeter-wide gap
between orifice and
skin. However, after
injections with saline
of volunteers in China
who carried hepatitis B
virus, 8% of subsequent
ejectates into
vials—representing the
next vaccinees in a
clinic or mass
campaign—were found by
polymerase chain
reaction assay to
contain hepatitis B
antigen. 722 High-speed
microcinematography also
revealed extensive
splashback from the skin
during injection with
MUNJIs. 496
This body of evidence
supports the conclusion
that the design of
MUNJIs is inherently
unsafe, and any reuse of
fluid pathways or
unsterile components
that are in direct or
indirect contact with
consecutive patients
should be abandoned.
Even if contamination
could be shown to be
extremely rare, it is
unlikely that
policymakers could be
convinced to set any
level of acceptable
risk.
Despite the
recommendations against
MUNJI use for
vaccination by public
health authorities, 723
, 724 and their
withdrawal by the US
military, 720 models
such as the MadaJet 608
(see Figure 61-5H ) and
SyriJet 607 continue to
be used in the United
States in dentistry and
podiatry and perhaps
other specialties. Also,
despite the Chinese
venue for the definitive
study documenting MUNJI
cross- contamination, 722
the Chinese Food and
Drug Administration was
reported in February of
2011 to have licensed
the Med-Jet 725 line of
MUNJIs in that country
for human applications,
726 as did Russian
regulators in April,
2011, 727 for
vaccination, physiatrics,
dermatology, and
mesotherapy indications.
MUNJIs allowed a single
health worker to
vaccinate 600 or more
patients per hour. 494 ,
530 , 532 , 546 The
withdrawal of the device
posed challenges for
conducting mass
immunization campaigns
for disease control
programs and in response
to pandemic or
bioterrorism threat.
Indeed, while the Soviet
biological warfare
effort was underway in
secret, 728 numerous
clinical trials were
published of high-speed
Russian MUNJIs capable
of rapidly protecting
soldiers or civilians
against potential
biowarfare agents such
as anthrax, botulism,
plague, smallpox, and
tularemia. 493 , 643–646
, 668 , 689 , 690 , 729
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