COVID-19 may make Lassa fever, cholera, other endemic diseases ‘deadlier’

•Researchers fear growing COVID vaccine hesitancy in developing nations
•Worry that pools of unvaccinated people could be source of new variants, such as Omicron

Recent studies have provided evidence that the emergence of COVID-19 has further aggravated the spread and treatment of diseases endemic to Nigeria, such as Lassa fever, cholera and meningitis, making them more infectious and deadlier. The situation also places extra burden on public health systems around the world.

Last month, an international team of researchers published an article highlighting the situation of Lassa fever in Nigeria following COVID-19, alongside public health strategies to contain it.

According to the study titled “Dual tension: Lassa fever and COVID-19 in Nigeria”, published in the journal Ethics, Medicine and Public Health, while there is no evidence that COVID-19 increases the risk of getting Lassa fever, there are reports of dengue-endemic countries with increased COVID- dengue co-infections such as Bangladesh, Columbia, and Ecuador.

The researchers concluded: “Overall, Nigeria continues to face COVID-19 and Lassa fever epidemic. While the numbers of confirmed cases have decreased, further actions and plans are needed to control and mitigate their negative impacts in Nigerians. This requires citizens, healthcare workers, and government to collaborate together to ensure best practices in community and in hospital. A strong health system is also crucial in public health emergency preparedness and managing of future epidemics.”

Lassa fever is a viral hemorrhagic zoonotic disease that is a continuous health issue in West African countries such as Sierra Leone, Liberia, Guinea and Nigeria. Ingestion and inhalation are the most common ways of transmission of Lassa fever. Patients generally get infected due to an exposure to food or household items, which are contaminated with urine or droppings of infected Mastomys rodents.

Lassa fever was first discovered in Lassa town, Borno State in Nigeria. It causes around 1,000,000–300,000 infections each year with approximately 5000 deaths in Nigeria.

While Lassa fever continues to be a public health challenge in Nigeria, Nigerians are also facing the COVID-19 pandemic. While Lassa fever is generally asymptomatic, severe cases require hospitalisation. Since COVID-19 and Lassa fever share the same clinical and laboratory facilities, management of Lassa fever becomes more difficult during the pandemic.

In fact, there are a lot of untested cases in Nigeria since there are only five modulator laboratories for Lassa fever testing and they are all located in either southern or central parts of the country. This makes transportation a challenge during the pandemic. A lack of physicians is another main challenge. With 40,000 doctors in the entire country of over 200 million, the health system is not strong enough to face both epidemics at the same time. Similar symptoms such as fever and headache in COVID-19 and Lassa fever, as well as other common tropical illnesses, complicate diagnosis, which delays initiation of therapy as patients may try self-medicating before seeking medical attention.

Also, a study titled, “Threats and outbreaks of cholera in Africa amidst COVID-19 pandemic: a double burden on Africa’s health systems”, published in the journal Tropical Medicine and Health, concluded that Africa is a high-risk area for the spread of cholera due to poor sanitation systems, lack of good drinking water and densely populated areas.

The researchers said disruption of healthcare services in high-risk areas due to COVID-19 therefore poses a great challenge in the fight against cholera. “As priority is now being shifted towards COVID-19 containment, data regarding cholera outbreaks are limited and unavailable in most African countries resulting in a lapse in contact tracing and the management of cholera patients as they are left undiagnosed and untreated. To win the fight against cholera and COVID-19 simultaneously, a ‘whole of Africa’ integrated approach involving collective advocacies, cross-border surveillance and information sharing, and stakeholder collaboration would be crucial for progress. This will ensure that no country is left behind because no one is safe until everyone is safe,” they said.

Every year, about four million cases and 143,000 deaths due to cholera are recorded globally, of which 54 per cent were from Africa, reported in 2016. The outbreak and spread of cholera have risen exponentially particularly in Africa. Coupled with the recent emergence of COVID-19 in Africa, the local health systems are facing a double burden of these infectious diseases due to their cumulative impact.

The researchers recommended: “The emergence of COVID-19 has disrupted the hard-won years of progress against cholera in Africa, but despite the paradigm shift in focus on COVID-19, it is critical that cholera must not become more forgotten. While the focus is on COVID-19, efforts such as improving water supply investment and sanitation, encouraging the use of oral cholera vaccines, strengthening cross-border surveillance, government, and stakeholder collaboration are necessary to counter the burden of cholera.”

Meanwhile, COVID-19 vaccine hesitancy has long been recognised as a problem in high- and middle-income nations. But in some of the world’s poorest countries, lack of access to vaccines has been a much bigger hurdle. Now researchers say that as doses are trickling in, resistance to getting vaccinated is also emerging as a major issue in those nations.

Scientists fear that persistent pools of unvaccinated people around the world will present a greater risk for the emergence of new variants of concern, such as Omicron. “When you have a lot of community transmission, that’s where variants will emerge,” said Jeffrey Lazarus, a global health researcher at the Barcelona Institute for Global Health, Spain. Addressing people’s hesitancy is therefore crucial, to curb viral spread and to avert hospitalizations and deaths, he said.

Scientists report that hesitancy might now be contributing to the slow uptake of vaccines in some nations where large proportions of the populations remain unvaccinated. These include South Africa — one of the nations where Omicron was first detected — Tanzania, the Democratic Republic of the Congo (DRC), Papua New Guinea and Nepal.

“We have more hesitant people in the global south than we ever thought we did,” said Rupali Limaye, a behavioural scientist at Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland, United States (U.S.).

Researchers say that countries might be struggling to get vaccines into arms for many reasons — some of which have nothing to with hesitancy — including poorly funded health-care systems, the fact that doses are often close to their expiry dates and logistical issues getting vaccines to remote regions. But people’s delay or refusal to get vaccinated is also part of the puzzle.

Studies have attempted to estimate the extent of hesitancy worldwide. One survey of nearly 45,000 participants in 12 countries — conducted before COVID-19 vaccines started being rolled out, and published in July — found that hesitancy was lower in the 10 low- and middle-income nations than in Russia and the United States.

Some reasons for hesitancy are shared globally, but there are also local differences. A major concern is safety; especially because the vaccines were developed and delivered rapidly and the recommendations for their use have often changed, say researchers.

Trust in governments is a related concern. The 32-country survey found that a belief that a government was handling the pandemic well was associated with higher acceptance of vaccines. Another analysis found that increased trust in medical and scientific authorities made people more likely to agree to vaccination.

In a recent unpublished survey of people in a number of countries, researchers found that mandates — such as requiring vaccination to travel by air or attend a workplace — could help to sway decisions. It found that, among people who were hesitant about COVID-19 vaccines, one-third said they would get vaccinated if they had to so that they could travel internationally.

“Opportunities to be vaccinated should also be integrated into existing services for the treatment and prevention of other infectious diseases, such as tuberculosis screening or distribution of Human Immuno-deficiency Virus (HIV) medications, which are accessible and familiar to people,” the researchers said.