London, Some low- and middle-income countries (LMICs) could experience a surge in HIV, tuberculosis (TB), and malaria deaths over the next five years because of disruption to health services caused by the Covid-19 pandemic, according to a new study, published in The Lancet Global Health journal.

The researchers have estimated that in areas heavily affected by these major infectious diseases, the impact of Covid-19 disruption on years of life lost could be of a similar scale to the direct impact of the pandemic itself.

Maintaining core services for HIV, TB, and malaria could largely mitigate the broader health impact of Covid-19, they said.

This includes ensuring access to antiretroviral therapy (Art), timely TB diagnosis and treatment, and early resumption of the distribution of long-lasting insecticide-treated nets (LLINs) and anti-malarial treatment.

"The Covid-19 pandemic and actions taken in response to it could undo the some of the advances made against major diseases such as HIV, TB, and malaria over the past two decades," said study researcher Timothy Hallett from Imperial College London in the UK.

"Our findings underscore the extraordinarily difficult decisions facing policymakers. Well managed, long-term suppression measures could avert the most Covid-19 deaths," Hallett added.

In the study, the research team assumed a basic reproductive number (R) - the average number of people each individual with the virus is likely to infect - of three to develop four different policy response scenarios to the Covid-19 pandemic.

These included no action, mitigation, which represents a 45 per cent reduction in R for six months using interventions such as physical distancing, suppression-lift -- a 75 per cent reduction in R for two months, or suppression, a 75 per cent reduction in R for one year.

Then they used transmission models of HIV, TB, and malaria to estimate the additional impact on health that could be caused in different settings.

Overall, the findings suggest that the impact of the pandemic varies according to the extent to which interventions against Covid-19 cause long disruptions to activities, and how successfully those measures reduce transmission of SARS-CoV-2, and avoid the health system being overwhelmed.

The greatest impact on HIV is projected to be from interruption to the supply and administering of ART, which may occur during times of high health system demand.

For TB, the greatest impact is predicted to be from reductions in timely diagnosis and treatment of new cases.

The model predicts that the greatest impact on malaria burden could result from interruption of planned net campaigns, which usually take place every three years.