BIOSPECTRUM | SEPTEMBER 2018 | http://www.biospectrumindia.com COVER STORY^25
Vaccine Development Phases
Pre-Clinical Trials
In vaccine development, the first step to
identifying a vaccine candidate is the pre-clin-
ical development stage. During this stage, the
researchers carefully select the antigen and
appropriate technologies, and then both in vitro
and in vivo tests are performed. The informa-
tion collected from these studies is vital to begin
safe clinical trials.
Phase I clinical trials
Phase I trials involve a small number of
healthy volunteers (around 20-50). The re-
searchers test the candidate vaccine for the first
time in humans in order to evaluate its safety,
determine a safe dosage range, and identify
vaccine-related side effects. This is achieved
by comparing the vaccine with a control or an
inactive substance called placebo (e.g. saline
solution). Phase I trials can also provide initial
data on the dose and the time needed between
vaccinations that will lead to an optimal im-
mune response. This first phase of the clinical
trials lasts 12 to 18 months.
Phase II clinical trials
If the candidate vaccine presents optimal
results in phase I, it will then undergo Phase II
trials during which the candidate vaccine is ad-
ministered to a larger group of people (around
100-300) to further evaluate its safety and im-
munogenicity. This phase explores more deeply
the right dose and administration schedule and
can last 2 or more years.
Phase III clinical trials
The most promising vaccine candidates
move into Phase III enrolling 3,000 to 50,000
subjects. The goal of this phase is to conduct a
large-scale safety and efficacy study in the rele-
vant patient population at which the vaccine is
aimed. Moreover during this phase concomitant
administration with other vaccines is tested.
Phase III clinical trials can last 3 to 5 years.
Phase IV or Pharmacovigilance
Once a vaccine has been marketed, pharma-
covigilance activities take place in order to carry
on a strict safety supervision of the vaccines
and detect, assess, understand, prevent and
communicate any adverse events following
immunisation, or of any other vaccine- or im-
munisation-related issues. Long-term follow-up
trials are often conducted to provide evidence
that the protection offered by the vaccine is
long-lasting.Bharat Biotech was recently in the news with respect
to the announcement of the National Technology
Award for 2018 from the Technology Development
Board, Government of India. This award on
innovative technologies, successfully developed
and commercialized from India was bestowed on
ROTAVAC, by the President of India Ram Nath
Kovind. ROTAVAC, a Bharat Biotech vaccine
that protects against diarrhoea became the first
indigenously developed vaccine to be incorporated in
the government-sponsored immunization campaign
this year. Besides, Bharat Biotech has reported
that its typhoid vaccine, Typbar TCV, has shown 87
per cent efficacy in trials. Currently, the company
is working on the phase I clinical trials for its
chikungunya vaccine.
“High investments in R&D and product
development, combined with 10-15 years of licensure
make vaccine development a painstaking venture.
Visualising return on investments is quite daunting
with vaccines having prolonged and highly detailed
regulatory procedures worldwide. Although the