A recent study by University of Witwatersrand Vaccines and Infectious Analytics Research (VIDA) reveals that people who have had both the COVID-19 vaccine and prior exposure to the virus, are less likely to get severe COVID-19 disease.
This type of immunity is called hybrid immunity, also sometimes called ‘super immunity’, and has been highlighted as the best way of reducing Severe illness and death in people who get infected with the SARS-Cov_2 virus, the virus that causes COVID-19.
The study, entitled ‘Population Immunity and COVID-19 Severity with Omicron Variant in South Africa’ reveals that we ideally need both types of immunity. According to the research, the discovery of hybrid COVID-19 immunity signals a hopeful turn in the fight against the COVID-19 pandemic.
Senior epidemiologist and research study author at Wits VIDA, Dr Portia Mutevedzi states that hybrid immunity is considered a double layer of protection against COVID-19.
“There are two types of immunity; natural immunity which we develop through exposure to the virus and vaccine induced immunity which develops as a result of vaccination,” Dr Mutevedzi adds.
The study researchers estimated the number of seropositive, that is people who had antibodies against SARS-CoV-2 within the general population of Gauteng. The results showed that individuals were 93.1% more likely to be seropositive if they had both the vaccine and prior exposure to COVID-19. This is especially important for diseases such as COVID-19 that result in severe illness and death. Vaccinating individuals even after they have had the disease ensures that they have higher levels of antibodies for a longer period.
As a result of this hybrid immunity, during the fourth wave there were far fewer cases of hospitalisations and deaths due to COVID-19, compared to earlier waves. The omicron variant resulted in 1 in 100 cases requiring hospitalisation while previously it was 1 in 24.
“The research proves that vaccination saves lives”, concludes Dr Mutevedzi. She adds that the public should be aware that due to the unpredictable mutation of COVID-19, new emerging variants may require us to get booster shots. Therefore, it is important especially for high risk-groups to get vaccinated as well as get booster doses even if they have previously suffered from COVID-19.