Influenza: Everything you need to know this winter

In 2022, there was a resurgence of influenza activity, following the Covid-19 pandemic. Currently, the National Institute of Communicable Diseases (NICD)  is unable to say what the flu trend will look like this winter. However, a prevalence in cases is expected, with a peak during winter months. In South Africa, the flu kills between 6000-11,000 people every year. 

According to the NICD, half of these deaths are in the elderly, and 30% are in people infected with HIV. The highest rates of hospitalisation are in the elderly (65 years and older), HIV-infected people and children who are under five.

Globally, there are between three to five million severe cases of influenza. Some of these resulted in deaths that are between 290 000 to 690 000, with the highest rates detected in Sub-Saharan Africa. 

During 2022, the NICD saw flu activity from January until August, dominated by three strains, influenza A(H1N1)pdm09, followed by A(H3N2) and B/Victoria strains. NICD Medical Epidemiologist, Dr Sibongile Walaza says for the first time since the pre-COVID period, influenza infections continued past the winter season through to the end of October.

Walaza says the majority of people will experience mild illness and will recover. But there are many individuals who can experience complications, or even die. 

How bad can influenza get?

Commonly known as “flu” it is a vaccine-preventable acute respiratory illness that is caused by the influenza virus. A person has to be infected with the virus in order to get sick. 

Severe cases can lead to decreased consciousness, strokes, impact heart function, heart attacks, and increased high blood pressure. Complications can cause renal failure.

How many strains of influenza are in SA?

There are currently three strains of influenza circulating in the country today.

“In the past three to four years, the dominant strain that we have been seeing in influenza infections is influenza A(H1N1)pdm09. When this strain emerged in 2009, it was new and became a pandemic known as swine flu. Today, this has become a seasonal strain and presents the same way as other influenza strains,” explains Walaza.

Another strain is A(H3N2) which is different but also has the same presentation. Followed by the B/Victoria. Walaza notes that the Influenza B/Yamagata strain has not been detected in the country since 2018. 

Do I have a cold or a flu – how do I know?

Cold symptoms affect the respiratory system and can cause sniffles, blocked noses, and chills. A cold can also be caused by the rhinovirus, which is the most common viral infection and dominant cause of a common cold. Respiratory syncytial virus (RSV), is a common respiratory virus that usually causes mild, cold-like symptoms. Most people recover in a week or two, but RSV can be serious,

With influenza, a person is sicker and presents with more severe symptoms. Including body aches and pains, headaches, fever, and a cough. 

“But some of the presentation does overlap, the main thing to know and understand is what the virus that is causing the illness is. Consulting a health provider when symptoms persist and are unchanging is best,” says Walaza.

I have the COVID-19 vaccine – am I safe from influenza? 

No, the COVID-19 vaccine can only protect you from getting COVID but not from getting influenza. The two vaccines and how they work in the body are not related.

People are still encouraged to have the influenza vaccines. Both the COVID-19 and influenza vaccines are available at public health facilities for all people who are eligible. 

Walaza confirms that it is also safe for individuals to get their COVID-19 booster shots on the same day as the influenza vaccine. 

Is the influenza vaccine safe for everyone?

Children can only get the influenza vaccine from six months and older. 

Individuals who have severe anaphylactic reactions, like really bad reactions to things like eggs, should consult their healthcare provider before vaccinating. 

One of the most important things for individuals to remember is that they should not get the vaccine if they are not feeling well or have any symptoms. 

How do I prevent severe disease and illness?

Get vaccinated. The influenza vaccine is the best available option for preventing influenza infections.

Walaza says it takes 14 to 21 days from the time of getting vaccinated to develop the antibodies that provide immunity against infection. 

However, it is not 100% effective. According to the Viral Watch programme, vaccine effectiveness for any influenza shot is 65%.

“It also depends on the person that receives the vaccine because it can sometimes work better in some individuals than others. It also depends on how well the contents of the vaccine match the strain of influenza.” – Health-e News