(Photo: EPA-EFE / Johan Nilsson)
Preparing for the third wave of Covid-19 pandemic must include a strong influenza prevention strategy, including vaccinations.
First published in the Daily Maverick 168 weekly newspaper.
Last year, SA was ravaged by Covid-19. To date, more than 1.5 million cases and more than 50,000 deaths have been confirmed. The real number of cases is likely to be more than 10 million, and we know that unexplained deaths, most of which are due to Covid-19, are well over 100,000. With the ongoing transmission by the community and the subsequent error-prone virus replication, new variants of SARS-CoV-2 are likely to emerge, which may favor further transmission.
Neither of us know when the third wave will happen, but most of us in the public health and science sectors believe that the introduction of Covid-19 vaccination will not be fast enough to prevent this and subsequent waves. If the next wave coincides with the winter respiratory season, especially a seasonal flu epidemic, a double blow will hit South Africa and its healthcare system.
Influenza kills around 10,000 people aged five and over in South Africa each year, a relatively small number compared to Covid-19 deaths last year, but still a high number. In addition, it causes between three and five million cases of serious illness and 290,000 to 650,000 deaths worldwide.
As with SARS-CoV-2, the flu is transmitted by lifting droplets from our upper respiratory tract and people who hand-transfer virus-carrying droplets are transferred from surfaces to the nose, mouth and eyes. Therefore, like Covid-19, it is prevented by masking, physical distancing, avoiding poorly ventilated indoor areas, good hand hygiene and isolation when symptoms occur, as well as testing. The latter is particularly important as the clinical disease is very similar to Covid-19.
It is perhaps not surprising that we recorded very few confirmed cases of influenza in South Africa and abroad in 2020 for several main reasons. First, the ultimate form of physical distancing – a hard lock – began right at the start of the flu season. The winter season usually starts in the Western Cape, as do other winter respiratory virus outbreaks. In a memo from the National Institute for Communicable Diseases dated April 9, 2020, an increase in influenza cases in the province was reported from late February to late March 2020. This mirrored what we saw in our hospitals where severe cases were admitted to intensive care the first few months of the year. However, cases of flu disappeared during and after the lockdown, so the tough lockdown appears to have helped shut down the lines of transmission for the disease. Lockdown also meant longer school closings, and since children are an important foundation for intense flu transmission, this transmission decreased.
However, when the lockdown was lifted, we did not see a resurgence of the flu. This has more to do with the effect of a lockout. As mentioned earlier, the flu virus like SARS-CoV-2 is transmitted through respiratory droplets, so masks, physical distancing and hand hygiene, among other things, most likely helped prevent a winter flu epidemic in 2020.
Finally, fears of a double blow in 2020 put heavy pressure on people to take flu shots. The World Health Organization recommends that certain high-risk populations nationally should be vaccinated against influenza, and SA publishes annual updates on which groups should be prioritized. A prioritization process is required as fewer than a million cans are procured annually. The high-risk groups include pregnant women (at particular risk of severe influenza pneumonia), people with HIV and other causes of immunosuppression, people with chronic lung, neurological or heart diseases, metabolic diseases such as diabetes and morbid obesity, and the elderly (65) and older ) and healthcare workers. The number of people in South Africa who should be vaccinated against influenza is in the tens of millions, but we can only work with what we have to offer. As we see with Covid-19, the hesitation of the vaccine or a perceived lack of risk means that some vaccine doses will not be used.
The lack of a tough lockdown in 2021, the recent move to Level 1, returning to school, and our poor compliance with public health measures ahead of the second wave of Covid-19 mean that SARS-CoV-2 may be in the winter will be affected by the flu.
What can you do to prevent the one-two blow from Covid-19 and flu? First, continue to adhere to public health policies that have become part of our everyday lives. Second, avoid poorly ventilated indoor areas where people congregate, which is fertile ground for superspreader events. Third, if you are in one of the groups at risk for serious complications from influenza, get the flu and Covid-19 vaccine as soon as possible.
There is no evidence that flu and Covid-19 vaccines interfere with each other. For pragmatic reasons, and because both can have mild reactions to the vaccines, it is probably best to distribute Covid-19 and influenza vaccines by two weeks.
Influenza vaccine is an inactivated vaccine that tells your immune system to recognize the influenza virus in the future and protect you from serious illness. Due to changes in the structure of the influenza virus over time, updated influenza vaccines must be administered each year. Influenza vaccine adverse events are rare and predominantly cause some sensitivity at the injection site and, in some people, symptoms such as a cold in the first 48 hours after vaccination. This is not because you are infected with influenza as the vaccine cannot cause infection. Rather, the symptoms some people experience relate to their immune system doing its job and charging itself to action. Because influenza vaccines are made in eggs, people with egg allergy should not have the inactivated influenza vaccine at their disposal and should consider the option of an alternative influenza vaccine that is not made in eggs.
Preparing the pandemic for the third wave of Covid-19 requires an understanding of the potential damage the added stress of a seasonal flu epidemic could do to our healthcare system and the people living in South Africa. Now is the time to step up prevention efforts and avoid mass gatherings and vaccinate high risk groups with the imminent arrival of the flu vaccine in SA and its introduction. DM168
Marc Mendelson is Professor of Infectious Diseases at Groote Schuur Hospital and the University of Cape Town.
This story first appeared in our weekly newspaper Daily Maverick 168, which is available to Pick n Pay Smart Shoppers for free at these Pick n Pay Shops.