Flu season is bad news for Covid-19 severity, scientists warn

As South Africa enters the influenza season, that combined with the high HIV and TB burden could spell disaster in terms of Covid-19 severity and deaths, eight leading scientists are warning.

Writing in the latest SA Medical Journal (SAMJ), they said it was crucial to employ surveillance strategies to evaluate the possible shared risks for both Covid-19 and the winter influenza, cautioning that co-infections would cause a spike in disease.

The authors are North West deputy vice-chancellor professor Nancy Phaswana-Mafuya; Dr Olive Shisana of the University of Cape Town; SA Medical Research Council president Dr Glenda Gray; Dr Nompumelelo Zungu of the Human Sciences Research Council; UCT Desmond Tutu HIV Centre’s professor Linda-Gail Bekker; Dr Lazarus Kuonza of the National Institute for Communicable Diseases; professor Khangelani Zuma of Wits University’s faculty of health sciences and professor Stefan Baral of the Johns Hopkins Bloomberg school of public health.

They found that co-infections with HIV and tuberculosis (TB) during the 2009 H1N1 outbreak were associated with disease severity and death.

“The incidence of H1N1 infections declined significantly during the transition from winter to spring in SA, suggesting that winter, the typical season for influenza, may have been conducive to the spread of the H1N1 virus. Similarly, the colder temperatures in winter may be conducive to the spread of the SARS-Cov-2 virus, as is the case for seasonal influenza.

“Fatalities among young adults killed by the H1N1 were related to TB, HIV, being pregnant and pre-existing metabolic conditions.

“Although the associations with HIV and TB are not yet clear in the preliminary Covid-19 data, it is highly likely the estimation of the coronavirus impact would be confounded by these two well-established epidemics.

“The latter would have serious implications, given that SA has the highest burden of HIV in the world: there were 240,000 new HIV infections in 2018 and the country has experienced 71,000 Aids deaths annually.

“Furthermore, there were 300,000 new TB infections in the same year and 63,000 TB-related deaths – 500 per 100,000 people. Two-thirds of these patients lived with HIV annually,” the experts said.

The clustering of HIV and TB led to the risk of “potentially increasing severity of the clinical course for those with Covid-19”.

The focus on the Covid-19 crisis was likely to compete with and possibly disrupt other public health services, including vaccinations, cancer screenings and non-communicable diseases programmes.

The scientists suggested that preliminary Covid-19 surveillance data could be strengthened through use of past pandemic data on respiratory pathogens to inform the structure and parameters of current mathematical models, including a sustained public health response.

Worsening the situation, with serious implications for correctly estimating the impact of Covid-19, were the country’s extreme socioeconomic disparities, which threatened the survival of vulnerable communities.

“The Covid-19-specific surveillance data employed since March is still severely restricted. The data varies by province, is incomplete and not generalisable, with severe restrictions on available test kits and laboratory capacity.

“By the time sufficient data is analysed, opportunities for epidemic mitigation may have been lost.

“Taken together, these factors suggest the importance of integrating multiple SA-specific parameters in mathematical models that estimate Covid-19 impacts and in optimally scaling up virus prevention and mitigation strategies,” the scientists said.

– brians@citizen.co.za

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