Abstract:
OBJECTIVE: The South African Thoracic Society, in conjunction
with interested stakeholders, published a Guideline for
Influenza Management in Adults in 1999. This year the South
African Thoracic Society (SATS) identified the need to revise
that guideline for the following reasons:
• To indicate the viral strains that are to be incorporated into
the vaccine for the 2008 season
• To add important new data regarding treatment of
influenza
• To add a section on influenza in children
• To clarify issues in managing and preventing influenza in
HIV-infected individuals.
INFLUENZA VIRUS: The influenza virus genus belongs to the
family orthomyxoviridae. The haemagglutinin (HA) protein
is the outermost protein, responsible for attachment to the
host receptor, and is critical in determining the host’s immune
response to the virus. Changes in the antigenic epitopes of
HA therefore allow the virus to escape the host’s specific
immune response. The genus is classified into three types,
A, B and C, on the basis of the antigenic epitopes of the
nucleoprotein (NP). Type A, which is widespread in nature in
birds and mammals, is the most important type clinically and
epidemiologically. It is further divided into subtypes on the
basis of the antigenic epitopes of the HA and neuraminidase
(NA) proteins. Each of the human subtypes H1N1, H2N2 and
H3N2 are further subdivided into strains on the basis of more
subtle antigenic properties of the HA protein.
INFLUENZA VACCINATION: Influenza vaccine is the mainstay of
influenza prevention strategies. All persons who are at high
risk of influenza and its complications because of underlying
medical conditions or who are receiving regular medical care
for conditions such as chronic pulmonary and cardiac disease,
chronic renal diseases, neuromuscular diseases, diabetes
mellitus and similar metabolic disorders, and individuals
who are immunosuppressed (including HIV-infected persons
with CD4 counts above 100 cells/μl and HIV-infected children
with CD4 counts >15%), should be vaccinated. Vaccines
should be given from at least 2 months prior to the onset of
autumn (March in South Africa). The recommended vaccine
formulation for 2008 is:
• A/Solomon Islands/3/2006 (H1N1) (IVR-145)
• A/Brisbane/10/2007 (H3N2) (IVR-147)
• B/Florida/4/2006 or B/Brisbane/3/2007.
TREATMENT OF INFLUENZA: Influenza illness is characterised by
the acute onset of systemic and respiratory signs occurring
in autumn or winter. Recommendations for the Prevention
and Control of Influenza have indicated that neither
amantadine nor rimantadine should be used for the treatment
or chemoprophylaxis of influenza A. NA inhibitors are
an important adjunct to influenza vaccination, in both the
prevention and treatment of influenza. Because of concerns
about the possibility of the development of viral resistance
with overuse of these agents, it is recommended that NA
inhibitors in the treatment of influenza should be reserved for
high-risk or sicker influenza patients.
