Lavina D'Souza hasn’t been able to collect her government supplied anti-HIV medication since the abrupt lockdown of India’s 1.3 billion people last month during the coronavirus outbreak.

Marooned in a small city away from her home in Mumbai, the medicine she needs to manage her disease has run out. The 43-year-old is afraid that her immune system will crash: “Any disease, the coronavirus or something else, I’ll fall sick faster.”

D’Souza said others also must be “suffering because of the coronavirus without getting infected by it”.

Also read: Is the number of Covid-19 deaths in Pakistan higher than being reported?

As the world focuses on the coronavirus pandemic, experts fear losing ground in the long fight against other infectious diseases like AIDS, tuberculosis (TB) and cholera that kill millions every year. Also at risk are decades long efforts that allowed the World Health Organisation to set target dates for eradicating malaria, polio and other illnesses.

With the coronavirus overwhelming hospitals, redirecting medical staff, causing supply shortages and suspending health services, “our greatest fear” is resources for other diseases being diverted and depleted, said Dr John Nkengasong, head of the Africa Centres for Disease Control and Prevention (CDC).

That is compounded in countries with already overburdened health care systems, like Sudan. Doctors at Al-Ribat National Hospital in Sudan’s capital, Khartoum, shared a document detailing nationwide measures: fewer patients admitted to emergency rooms, elective surgeries indefinitely postponed, primary care eliminated for non-critical cases, and skilled doctors transferred to Covid-19 patients.

Similar scenes are unfolding worldwide. Even in countries with highly developed health care systems, such as South Korea, patients seeking treatment for diseases like TB had to be turned away, said Hojoon Sohn, of Johns Hopkins Bloomberg School of Public Health, who is based in South Korea.

About 30 per cent of global TB cases — out of 10 million each year — are never diagnosed, and the gaps in care are concentrated in 10 countries with the most infections, Sohn said.

“These are people likely not seeking care even in normal circumstances,” he said. “So with the Covid-19 pandemic resulting in health systems overload, and governments issuing stay-at-home orders, it is highly likely that the number of TB patients who remain undetected will increase.”

In Congo, already overwhelmed by the latest outbreak of Ebola and years of violent conflict, the coronavirus comes as a measles outbreak has killed over 6,000 people, said Anne-Marie Connor, national director for World Vision, a humanitarian aid organisation.

“It’s likely we’ll see a lot of ‘indirect’ deaths from other diseases,” she said.

The cascading impact of the pandemic isn’t limited to treatment. Other factors, like access to transportation during a lockdown, are threatening India’s progress on TB. Patients and doctors can’t get to clinics, and it’s difficult to send samples for testing.

India has nearly a third of the world’s TB cases, and diagnosing patients has been delayed in many areas. Dr Yogesh Jain in Chhattisgarh — one of India’s poorest states — and other doctors fear that means “TB cases would certainly increase”.

Coronavirus-related lockdowns also have interrupted the flow of supplies, including critical medicine, protective gear and oxygen, said Dr Marc Biot, director of operations for international aid group Doctors Without Borders.

“These are difficult to find now because everybody is rushing for them in the same moment,” Biot said.

The fear of some diseases resurging is further aggravated by delays in immunisation efforts for more than 13.5 million people, according to the vaccine alliance GAVI. The international organisation said 21 countries are reporting vaccine shortages following border closures and disruptions to air travel — mostly in Africa — and 14 vaccination campaigns for diseases like polio and measles have been postponed.

The Measles & Rubella Initiative said measles immunisation campaigns in 24 countries already are delayed, and it fears that more than 117 million children in 37 countries may miss out.

Dr Jay Wenger, who heads polio eradication efforts for the Bill & Melinda Gates Foundation, said recommending the suspension of door-to-door polio vaccinations was difficult, and while it could lead to a spurt in cases, “it is a necessary move to reduce the risk of increasing transmission of Covid-19”.

Programmes to prevent mosquito-borne diseases also have been hampered. In Sri Lanka, where cases of dengue nearly doubled in 2019 over the previous year, health inspectors are tasked with tracing suspected Covid-19 patients, disrupting their “routine work” of destroying mosquito breeding sites at homes, said Dr Anura Jayasekara, director of Sri Lanka’s National Dengue Control Unit.

During a pandemic, history shows that other diseases can make a major comeback. Amid the Ebola outbreak in Guinea, Liberia and Sierra Leone in 2014-16, almost as many people died of HIV, tuberculosis and malaria because of reduced access to health care.

Rashid Ansumana, a community health expert in Sierra Leone who studied the Ebola outbreak, said the coronavirus’s “impact will definitely be higher”.

Health providers are trying to ease the crisis by giving months of supplies to people with hepatitis C, HIV and TB, said Biot of Doctors Without Borders.

As countries face difficult health care choices amid the pandemic, Nkengasong of the Africa CDC warns that efforts to tackle other diseases can’t fall by the wayside.

“The time to advocate for those programmes is not when Covid is over. The time is now,” he said.