FURTHER INFORMATION REQUESTED BY THE COMMITTEE ON 13-14 DECEMBER CONCERNING NIMR

1.   Copies of the correspondence relating to the NIMR pathogen containment facilities

  Paper copies of various key letters and emails have been sent under a separate cover. A list is at the Annex. This correspondence is not complete but we believe contains the most relevant documents (not published).

2.   Copies of correspondence between MRC and MI5 relating to security at Mill Hill and at the NTH site

  We have consulted MI5 and have been informed that we should not release copies of our correspondence with MI5 as requested by the Committee. As the Committee is aware, it is a long standing principle followed by successive governments that material is not disclosed which could impede the operational effectiveness of the intelligence and security agencies and/or could be harmful to national security.

3.   An explanation of the differences between level 3 and level 4 containment facilities and equipment, and which level would be required by NIMR, should avian flu mutate into a form transmissable between humans

  There are two different sets of requirements concerning handling of samples containing certain suspected or known strains of flu virus, one set by the Health and Safety Executive and the other by DEFRA. The former follows guidance from the Advisory Committee on Dangerous Pathogens (ACDP); the latter is determined by the Specified Animal Pathogens Order 1998 (SAPO).

  The full details are at:

—  www.hse.gov.uk/biosafety/diseases/acdpflu.pdf ; and

—  www.defra.gov.uk/animalh/diseases/pathogens/index.htm

  [The first of the above documents also contains an explanation of DEFRA requirements (ie SAPO Level 4 requirements)].

  ACDP levels are constructed to protect the worker and prevent external release that might endanger humans. The DEFRA levels are determined on the basis of ensuring that the agent is not released into the environment, thus endangering wildlife.

  The DEFRA regulations state that specified strains of Avian flu, including H5N1, must be handled at SAPO Level 4.  The requirements for working with H5N1 at SAPO Level 4 are at www.defra.gov.uk/animalh/diseases/pathogens/category4.htm.

  The current advice provided by HSE for those working with avian flus such as H5N1 is that all work with the specified strains requires ACDP Containment Level 3, with the strong recommendation that closed fronted safety cabinets are used. ACDP Level 4 is not required for any flu work.

  The key additional measures required for SAPO Level 4 over and above full ACDP Containment Level 3 are:

—  Single high-efficiency particulate air (HEPA) filtered inward air; double filtered exhaust.

—  Inflow interlocked with extract air.

—  An airlock at entry and exit.

—  Full change and shower on exit.

—  Work can be done in Class I/III hybrid cabinets, with mandatory use of the Class III mode if there is significant risk of aerosol generation.

—  The laboratory should be maintained at -75 Pascals with respect to atmosphere. This is a greater differential pressure than is applied in ACDP CL3 laboratories and has implications for wall fabric and coatings.

—  The laboratory must be secure against intruders, and fitted with an intruder alarm.

—  All hazardous waste decontaminated by validated means within the suite.

—  Double ended autoclave for solid waste.

—  Validated liquid waste stream (involving use of dunk tank. The tank must be provided with the means of isolating it from areas that may be fumigated, in case the chemicals used are incompatible with the fumigant).

  With reference to the specific question on what would happen in a pandemic, the HSE document contains the following:

    "  Planning for pandemics

During the first stages of a human pandemic, ie before a strain is routinely circulating in the UK, then all intentional work with such viruses should be carried out at CL3.  However, once the virus is the predominant circulating strain and a vaccine is available, it can be handled at CL2.  However, if available information indicates that virus is still highly virulent even though it is the predominant strain, then CL3 is still appropriate."

  Although H5N1 attracts much attention at present, DEFRA Level 4 would still be required if a laboratory were required to look for the presence of other known avian pathogenic strains of flu in samples sent to it.

  [Any relaxation of containment standards required as a result of endemic avian flu (from SAPO 4 to 3) or pandemic human flu (ACDP 3 to 2) would be entirely strain specific as well as dependent upon available effective human vaccine. If NIMR were to extend its research to other avian strains, or to continue its present role as recognised reference laboratory, then SAPO 4 would still be required].

January 2007