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Smallpox Vaccine Stockpiling and ACAM


									                                                                       Technology & Services

                                               Smallpox Vaccine Stockpiling and ACAM2000

       a report by

The Threat of a Smallpox Attack                            tonnes of variola virus. These stocks are yet to be
                                                           accounted for and it is not clear where the thousands
Since the events of 11 September 2001, there have          of Russian scientists who worked on biological
been anthrax attacks in the US, ricin letters posted       weapons research programmes are now employed.
within the UK and letters laced with adamsite sent to
government offices in Belgium. The world is                The US lists Iran, Iraq, Libya and North Korea as
realising that terrorists will use biological weapons to   countries under suspicion of having variola virus stocks.
further their aims. Today, the global concern is no        No conclusive evidence that variola proliferation has
longer about the ‘cold war’ threat of biological           actually taken place has been presented in public.
warfare between superpowers, but of biological             According to the Washington Post1, a US intelligence
terrorism and biosecurity.                                 review also indicated that the Al Qaeda network has
                                                           made attempts to obtain the virus.
Independently, the US Centers for Disease Control
and Prevention (CDC) and Russian scientists have           Governments around the world are now dedicating
identified smallpox (variola) as the greatest              resources to prepare to deal with and prevent
bioterror threat. The virus is highly contagious, has      potential bioterrorist attacks. Many countries are
a low infective dose, is stable, could be easily           stockpiling the smallpox vaccine as a deterrent and
deployed and kills approximately one-third of              management measure should such an attack occur.
those it infects. As a result, variola is capable of       Acambis is the world’s leading supplier of smallpox
affecting public health and medical infrastructures        vaccine for government stockpiles.
on a very large scale.
                                                           International Support for Stockpiling
Following a global intensified eradication
programme, the World Health Organization                   The WHO is supportive of individual countries
(WHO) declared the world free from smallpox –              developing national stockpiles of smallpox vaccine.
once the most feared of diseases – in 1980. It is sad      In addition, it has stated its intent to build a global
that 25 years after one of the greatest achievements       virtual stockpile of vaccine, relying on countries to
in public health there is now fear of the deliberate       donate a portion of their national stocks. Several
release of the variola virus. Equally disturbing is the    countries in North America and Asia have
fact that the achievement of eradication has made          announced that they are stockpiling vaccine and, in
the virus even more dangerous as a biological              addition, most EU member states have, or are
weapon, because the cessation of vaccination has           acquiring, stockpiles of smallpox vaccines. A few of
left the majority of the world’s population                these countries have ordered or are planning to
vulnerable to the disease.                                 order new, second-generation vaccines.

Officially, the variola virus is only located in two       The US has stockpiled one dose per citizen of the
places – the CDC in Atlanta, US and the Vector             smallpox vaccine. As part of the national stockpile it
laboratories in Novosibirsk in Russia – both working       has purchased 182 million doses of Acambis’ new,
under strict protocols. It can never be fully verified,    second-generation vaccine, ACAM2000. Within the
however, that the countries destroyed all vials of         EU, the size of the national stockpiles in relation to
variola after the eradication programme ended.             the national population, ranges from enough to
Several scientists who defected from the former            provide one dose per citizen to enough for one
Soviet Union have confirmed that stocks of biological      citizen in 30.2 Acambis has supplied ACAM2000 to
weapons were developed, including a stockpile of 20        several countries within the EU.

1. 5 November 2002.
2. Commission of the European Communities, Brussels, 2 June 2003.                                                      1

              Technology & Services

    ACAM2000 – Second-generation                                   generation vaccine used during the global
    Smallpox Vaccine                                               eradication programme.

    Under US Food and Drug Administration (FDA)                 • It is manufactured using modern cell-culture
    investigational new drug (IND) applications, Acambis          techniques, designed to comply with current
    is currently able to supply two investigational               good manufacturing practice (GMP) standards.
    smallpox-related products to governments. They are
    Acambis’ new, second-generation smallpox vaccine –          • It is a clonal vaccine – there is a single type of
    ACAM2000 – and Cangene Corporation’s Vaccinia                 vaccinia virus present, which has been
    Immune Globulin (VIG), a product that can be used to          well characterised.
    treat some of the potential adverse events that may
    occur following smallpox vaccination.                       • It is routinely manufactured under serum-free
                                                                  conditions to minimise the chance of any
    The old first-generation smallpox vaccines were used          adventitious viruses or animal proteins
    effectively in the eradication of smallpox. The majority      being present.
    of stocks now available, however, were manufactured
    20 or more years ago by methods that are unacceptable       • Production on a continuous cell line provides a
    by today’s standards. First-generation vaccines were          predictable, standardised manufacturing process.
    created from lymph collected from pustules on the skin
    of vaccinia-infected calves or other large animals. The     • It has undergone clinical testing under an
    concerns about first-generation vaccines are two-fold.        investigational new drug (IND) from the FDA.
    Firstly, the vaccines are heterogeneous and so there is a
    possibility that some highly virulent subtypes could be     The clinical programme for ACAM2000 was
    present. Secondly, given that the stocks were               designed to meet the requirements for licensure in
    manufactured over 20 years ago, before recent               the US, Europe, Australia and Canada.
    technological advances such as polymerase chain
    reactions (PCRs) were available, there is the likelihood    The partner of Acambis, Baxter Healthcare
    that adventitious animal viruses could be present. For      Corporation, facilitates the distribution of both
    licensure in the days of the eradication programme, the     ACAM2000 and VIG. In addition, the partnership
    first-generation vaccines were only required to             extends to the development of a modified vaccinia
    undergo potency and bioburden tests.                        ankara (MVA) vaccine. MVA is a weakened form of
                                                                the current smallpox vaccines and the aim is that it
    The goal of Acambis was to develop a new, second-           will allow the safe inoculation of ‘at risk’ people with
    generation vaccine equal to the first-generation            weakened immune systems. MVA is currently
    vaccine in terms of efficacy and compliant with the         undergoing clinical testing under a US
    modern criteria for licensure as outlined by the FDA        IND application.
    and the European Agency for Evaluation of
    Medicinal Products (EMEA).                                  Through the development of this portfolio of products,
                                                                Acambis is at the forefront of the fight against the
    • ACAM2000 is derived from Dryvax®, a first-                smallpox bioterror threat. ■


                                         BUSINESS BRIEFING: CLINICAL VIROLOGY & INFECTIOUS DISEASES 2004

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