Quadrivalent flu vaccine protects against 2021 flu strains

Annual vaccination is still vital

Johannesburg, 9 June 2021: Each year severe illness caused by influenza (flu) affects between 3 and 5 million people worldwide,1 with up to 650 000 deaths – over 11 000 of these in South Africa.1,2

Almost 50% of the 47 000 South Africans afflicted by flu every year require hospitalisation.2 Preventing severe flu will decrease the burden on the healthcare system.3 Vaccination against the flu is therefore strongly recommended by the National Institute for Communicable Diseases, as co-circulation with SARS-CoV-2 is very likely.3

Flu and COVID-19 have similar modes of transmission and some overlapping clinical presentation.3 The signs and symptoms of uncomplicated flu overlap with those of mild COVID-19, and complications of these two conditions may be similar.3 However, the onset of severe-COVID-19 or complications usually occurs later, in the second week of illness, compared to that of flu, which usually occurs within the first week of illness.3 Although there may be similarities in symptoms, COVID-19 and flu are two separate diseases that require two completely different vaccines.4


The World Health Organization (WHO) strongly supports administration of the flu vaccine amidst the COVID-19 pandemic.5 Preventing and reducing the severity of illness associated with flu will ease the burden on those who are most vulnerable, and on the healthcare system.5 While hand and respiratory hygiene, social distancing and travel restrictions may have reduced the transmission of flu in 2020, flu transmission may increase as global travel restrictions ease.5

The WHO monitors the epidemiology of flu viruses across the world and each year makes recommendations about strains to be included in the vaccine for the upcoming flu season. Separate recommendations are made for the Southern and Northern Hemisphere vaccines.6


The recommended quadrivalent flu vaccine components for 2021 for the Southern Hemisphere includes an A/Victoria/2570/2019 (H1N1) pdm09-like virus, an A/Hong Kong/2671/2019 (H3N2)-like virus, a B/Washington/02/2019 (B/Victoria lineage)-like virus, and a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.6

The Vaxigrip Tetra quadrivalent flu vaccine by Sanofi Pasteur complies with the WHO’s Southern Hemisphere recommendations for the 2021 season.7


Says Dr Nasiha Soofie, Medical Head at Sanofi Pasteur Vaccines: “It is important to note that with all the safety measures undertaken last year, we didn’t really have a flu season in SA, so herd immunity has not been established. The flu is capable of rebounding and having unexpected, severe consequences. It is still very important that healthcare professionals encourage patients to get their flu vaccines this year, as the flu virus is a different type of virus to COVID-19, so the two vaccines work differently.”

In addition, the Department of Health highly recommends that all healthcare workers are vaccinated.8 Other priority groups include Individuals aged > 65 years, those with cardiovascular disease (including chronic heart disease, hypertension, stroke and diabetes), or chronic lung disease (including asthma and chronic obstructive pulmonary disease), individuals living with HIV and AIDS, and pregnant women.8


The Department of Health advises that the flu vaccine can be given concurrently with other injectable, non-flu vaccines, but must be administered at different injection sites.8 The only exception regarding co-administration is with regard to COVID-19 vaccines – no vaccine may be co-administered with these.8 As per the National Institute of Communicable Diseases (NICD), the COVID-19 vaccine must be scheduled with at least a 14-day interval between it and any other vaccine.8

  • The flu vaccine should not be administered to people with history of anaphylaxis (severe allergic/hypersensitive reactions) following receipt of any vaccine component, including eggs, neomycin or polymyxin antibiotics; those with a history of severe reaction to previous flu vaccination; people who developed Guillain–Barré syndrome within 6 weeks of receiving a flu vaccination; and children < 6 months.8
  • The flu vaccine must be administered intramuscularly, by injection into the upper arm (deltoid) for most people, and in the antero-lateral thigh for infants and younger children.8


Says Dr Soofie: “Flu vaccination is a critical public healthcare measure, considering the possible co-circulation of both the flu and SARS-COV-2 viruses in the absence of a hard lockdown. It is important to remember that the COVID-19 vaccine will not prevent the flu and vice versa; therefore, it is critical to ensure that the public is vaccinated against both. It is also important to protect healthcare workers and ensure they are able to work and to reduce any additional burden on the health system.”



1 World Health Organization. Influenza (seasonal). https://www.who.int/news-room/fact-sheets/detail/influenza-(seasonal). Accessed 24 May 2021.

2 Blumberg L, Cohen C, Dawood H, et al. Flu NICD recommendations for the diagnosis, prevention, management and public health response. Available from: http://www.nicd.ac.za/wp-content/uploads/2017/03/Flu-guidelines-rev_-23-April-2018.pdf. Accessed October 2019.

3 NICD. 2021. Influenza: Recommendations for the diagnosis, management, prevention and public health response guidelines 2021.

4 World Health Organization. Coronavirus disease (COVID-19): Similarities and differences with influenza. Available from: https://www.who.int/emergencies/diseases/novel-coronavirus-2019/question-and-answers-hub/q-a-detail/coronavirus-disease-covid-19-similarities-and-differences-with-influenza. Accessed 26 May 2021.

5 World Health Organization. WHO SAGE Seasonal Influenza Vaccination Recommendations during the COVID-19 Pandemic. Available from: https://www.who.int/immunization/policy/position_papers/Interim_SAGE_influenza_vaccination_recommendations.pdf?ua=1. Accessed November 2020.

6 World Health Organization. Recommended composition of influenza virus vaccines for use in the 2021 southern hemisphere influenza season. Available from: https://www.who.int/publications/m/item/recommended-composition-of-influenza-virus-vaccines-for-use-in-the-2021-southern-hemisphere-influenza-season. Accessed 24 May 2021.

7 Vaxigrip Tetra Package Insert.

8 Department of Health. Influenza Vaccination Guide 2021.