Influenza Season

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The 2018 influenza season has started. Every year during winter months, May to August, South Africa experiences an increase in influenza circulation. The influenza season is the period when influenza circulates in South Africa and during this time we see a marked increase in cases of influenza in the community as well as healthcare facilities. The influenza season is considered to have started when the when influenza detections in the influenza-like illness surveillance sentinel surveillance programme (Viral Watch) rise above the seasonal threshold, as determined by the Moving Epidemic Method (a sequential analysis using the R Language, available from http://CRAN.R-project.org/web/package=mem). The seasonal threshold was reached in the week ending 6 May. While there have been low levels of influenza circulating since mid-April, the number of specimens testing positive for influenza in all three surveillance programmes (influenza-like illness in public health and private practitioners and pneumonia surveillance), has increased since early May. To date, the majority 117/118 (99%) of influenza positive samples for this season, detected by these programmes, have been identified as influenza A(H1N1)pdm09. This strain was the strain that emerged globally in 2009. In 2018 this strain of influenza behaves like a normal strain of seasonal influenza and patients infected with this strain should be treated like any other seasonal influenza case. There is NO requirement to report or notify individual cases of this strain of influenza.

Influenza vaccination
Influenza vaccination, which provides protection against at least three strains of influenza each season, remains the most effective measure to prevent illness and possibly fatal outcomes. Protecting those who are at increased risk of severe influenza outcomes plays an important role in the management of respiratory illnesses. Individuals at risk of influenza and severe disease include among others the pregnant women and those vulnerable due to pre-existing illnesses or risk factors. Vaccines should be given sufficiently early to provide protection for the influenza season, though it is never too late to vaccinate. A protective antibody response takes about 2 weeks to develop. The 2018 influenza vaccine has been available in South Africa since the middle of April and it can be accessed at local clinics and private providers (pharmacies and private practitioners). Clinicians are encouraged to vaccinate individuals in the groups that are targeted for influenza vaccination. Influenza NICD recommendations for diagnosis, prevention, management and public health response, can be accessed at http://www.nicd.ac.za/wp-content/uploads/2017/03/Influenza-guidelines-rev_-23-April-2018.pdf