COVID-19 pandemic ‘could be quite damaging’ to efforts to end other diseases
In May, modeling commissioned by the Stop TB Partnership showed that a lockdown of just 3 months due to the COVID-19 pandemic could set the global fight against tuberculosis back at least 5 to 8 years.
Global efforts against other diseases, including malaria and polio, also have been negatively impacted by the pandemic.
“What the pandemic is doing on different fronts could be quite damaging,” Dennis Falzon, MD, a medical officer for WHO’s Global Tuberculosis Program, told Infectious Disease News.
Not every effort is experiencing setbacks. Currently, eradication efforts for Guinea worm are progressing. As of May 31, there were only 15 reported human cases of Guinea worm in 2020, and it is estimated that the total number of cases for the year will be at least 50% lower than the 2019 total of 54.
“COVID-19 or not, we are expecting pretty significant reductions from last year,” Adam Weiss, MPH, director of the Carter Center’s Guinea Worm Eradication Program, said in an interview.
Infectious Disease News spoke with several experts regarding efforts to end various diseases and how the pandemic is affecting those endeavors.
COVID-19 and TB: ‘Double trouble’
In 2015, WHO began a 20-year global initiative to eliminate TB titled The End TB Strategy. The goal is to end the global TB epidemic by reducing TB deaths by 95% and cutting new cases by 90% by 2035.
According to Falzon, the fight against TB — still the world’s No. 1 infectious killer — is being impacted in several ways by COVID-19. The same patients who do poorly with COVID-19 — patients with diabetes, lung disease or patients who are older — also are less likely to do well TB.
“In a pandemic situation, many TB patients will get COVID-19 and this will be double trouble for patients with risk factors for a poor outcome,” Falzon said.
There also have been disruptions in health services caused by lockdowns and curfews, and a hesitance by sick people to seek medical care for fear of encountering COVID-19, he said. On top of that, health services — including staff treating TB — have been redirected to address the pandemic.
“Very often, in many poor countries, the frontline services that were providing TB care are actually the same ones that would be solicited most for COVID-19,” Falzon said. “We need the TB community and the TB health services to contribute to the COVID-19 response, because they are well positioned to do that. On the other hand, it’s this awful balance of trying to make sure that you maintain this essential service or continue to expand it, and to be creative to look for openings to manage both conditions at once, effectively and efficiently.”
A key component of The End TB Strategy is prevention: finding and treating TB patients earlier to cut transmission in the community. These strategies are being imperiled by COVID-19.
“If you reduce case detection by even one-quarter or 3 months, it’s estimated that will set us back in terms of mortality gain by at least 5 years,” Falzon said. “So, all the gain we have had in the last 5 years could be lost just by having an interruption of 3 months with just the reduction of 25%. That adds 200,000 more TB deaths every year.”
According to Falzon, reserves of bacillus Calmette-Guérin (BCG) vaccine — a TB vaccine that is used widely in other countries but not in the United States — have been channeled to vaccinate health care workers in some countries “because of the belief that this will protect them from getting COVID-19 or from suffering worse outcomes if infected.”
“We strongly discourage this,” he said. “There are ongoing trials now looking at this, and before we have results, we insist that people conserve their stocks of BCG where it’s needed, to protect from TB.”
Falzon noted that a TB vaccine in development could have an impact on elimination efforts down the line. The candidate vaccine, M72/AS01E (GlaxoSmithKline), was 50% effective at preventing adults from progressing to pulmonary TB for at least 3 years, according to an analysis published last year in The New England Journal of Medicine.
“This vaccine could be the one that we are waiting for,” Falzon said. “There are other candidate vaccines, it is just that this one has advanced a bit more, and we hope that this will break new ground because that is really needed.”
Malaria: ‘Flatlining’ progress
WHO’s stated malaria elimination goals include decreasing malaria incidence and mortality by 90%, eliminating malaria in at least 35 countries and preventing resurgence of malaria in countries that have been declared free of the disease, all by 2030.
As of now, “we’re not on track to meet those goals,” and the pandemic could make matters worse, said Kimberly A. Lindblade, PhD, the unit head of WHO’s Malaria Elimination Team.
“We know that it will have an impact, we just haven’t quantified that impact yet,” Lindblade told Infectious Disease News. “There have been some modeling projections under different scenarios.”
According to one modeling analysis published by WHO in April, interrupted access to antimalarial medicines and disruptions to insecticide-treated net campaigns because of COVID-19 could double the number of malaria deaths — to 769,000 — in sub-Saharan Africa in 2020 compared with 2018.
Lindblade said malaria services were disrupted in Africa early in the pandemic because of inaccurate messaging.
“They were told if you have a fever, stay at home, which is actually exactly what they should not do if you’re a child with a fever in a malaria-endemic country,” she said.
Lindblade also noted delays in campaigns to provide insecticide-treated bed nets and indoor residual spraying, but said the effects of the delays have not yet been quantified.
“We’re working very closely with countries to try and address gaps in their commodities, delays, all of that, trying to help them work through those issues and get things back on track,” she said. “But undoubtedly, there will be an impact, and we’re just doing everything we can right now to mitigate it.”
The pandemic aside, Lindblade said there is not enough money for malaria eradication efforts. WHO launched a large pilot program last year that will immunize approximately 360,000 children in three African countries with a vaccine, RTS,S (GlaxoSmithKline), that has been shown to significantly reduce malaria in children. But in general, the annual World Malaria Report has consistently warned in recent years that progress against malaria has stalled.
“Overall, globally, we were making a lot of progress from the beginning of 2000 until around 2015. There were substantial declines in the incidence rate of malaria, as well as the mortality rate,” Lindblade said. “And then somewhere around 2015 or 2016, the progress stalled. And we’ve been sort of flatlining since then.”
‘Unfettered’ polio transmission
In April, the Global Polio Eradication Initiative (GPEI) recommended that all polio vaccination campaigns be postponed until the second half of 2020 because of the pandemic, and that nonendemic countries responding to polio outbreaks suspend those efforts until at least June 1.
“All of those campaigns have been delayed, which has allowed unfettered polio transmission in some places,” Walter A. Orenstein, MD, professor of medicine and associate director of the Emory Vaccine Center, told Infectious Disease News.
In July, WHO announced that polio vaccination campaigns had resumed “under strict COVID-19 prevention measures” in WHO’s Eastern Mediterranean region, including in Pakistan, one of the two remaining countries — along with Afghanistan — with circulating wild poliovirus. WHO called the suspension of polio vaccination campaigns “necessary to protect both heath workers and communities from COVID-19,” but said the disruptions have resulted in “expanding transmission” in the region.
As of July 21, there were 85 reported cases of wild poliovirus globally — 56 in Pakistan and 29 in Afghanistan — an increase of 21 cases over the same period last year. There were 210 reported cases of circulating vaccine-derived poliovirus, up from 69 cases at the same time in 2019.
Orenstein noted the two things that limit spread — detecting those who are infected and administering the bivalent oral poliovirus vaccine, which protects against the remaining wild polio strains, type 1. The trivalent vaccine, which also protected against the now-eradicated type 2 poliovirus, was discontinued in 2016. However, the discontinuation was done at a time when there were undetected type 2 circulating vaccine-derived polioviruses (cVDPVs) present, which led to outbreaks after the switch, Orenstein said. The response to those outbreaks with monovalent live oral poliovirus type 2 vaccine generated more cVDPV2 outbreaks in some areas.
“The problem is, if you don’t do a good job with high coverage so that you vaccinate virtually everybody who needs to be vaccinated, the vaccine can create new circulating vaccine-derived polioviruses through circulation in susceptible people,” Orenstein said.
He said there is hope that a genetically stable polio vaccine — a further attenuated version of the Sabin oral polio vaccine that does not “revert ... to neruovirulence” — will be available this year.
“The preliminary data were very good,” he said. “This should allow us to stop the current cVPDV2 outbreaks and not generate any more through our response.”
‘Encouraging progress’ against Guinea worm
Currently, the COVID-19 pandemic has not interrupted eradication efforts for Guinea worm, Weiss said. The 15 human cases so far this year is the lowest number that The Carter Center has ever seen.
The Carter Center was founded in 1982 by President Jimmy Carter and First Lady Rosalynn Carter, in partnership with Emory University. One of its main missions is the eradication of Guinea worm.
In 1986, Guinea worm was estimated to affect an estimated 3.5 million people per year in 21 countries in Africa and Asia. Now, only five countries still experience cases — Angola, Chad, Ethiopia, Mali and South Sudan.
“We’re making encouraging progress, particularly in Chad, where since 2012, we’ve been observing infections of Guinea worm in dogs,” Weiss said. “We’re starting to see very encouraging evidence that we are stopping the spread of transmission and reducing overall infection numbers.”
Weiss said the program continues to make progress in Mali and Ethiopia as well. However, there was a setback in Ethiopia this year, when seven people were infected, which Weiss said was discouraging. However, they were able to pinpoint where those individuals were retrieving water and believe the water was infected by animals — most likely dogs or baboons, he said.
“Globally, we’re still talking about a handful of countries where Guinea worm exists, and of course, the historic context — 3.5 million down to a few dozen cases,” Weiss said. “By the end of this year, I would expect that we’ll have less than 25 cases.”
The spread of Guinea worm recently has come from animals — both wild and domestic. Weiss said that at first, it was harder to deal with animal infections because the global program did not realize it was possible.
Recently, Ethiopia restricted the movement of domestic dogs in an effort to prevent the spread of Guinea worm. In Chad, the health ministry enacted proactive tethering, in which dogs are kept at home and not permitted to forage during peak periods of transmission. Chad has seen a 25% reduction in canine cases of Guinea worm.
“Everything is coming together in a perfect storm of sorts, and we’re starting to see the fruits of that labor, though there is potential for COVID-19 to interrupt progress,” Weiss said. “Although the program continues to operate, the potential impact of intermittent travel restrictions on supervision will not be realized until next year, due to the 10 to 14 month incubation period [of Guinea worm].”
Progress against other NTDs ‘a big concern’
In 2018, African health leaders publicly committed to treat neglected tropical diseases as a top health priority on the same level as malaria.
According to Peter J. Hotez, MD, PhD, dean of the National School of Tropical Medicine and professor of pediatrics and molecular virology and microbiology at Baylor College of Medicine, USAID’s Mass Drug Administration is leading efforts to eliminate neglected tropical diseases. Because of the COVID-19 pandemic, however, Hotez worries these efforts may be slowed, interrupted or halted.
“The Mass Drug Administration’s program is huge in continuing eradication efforts toward lymphatic filariasis, river blindness and trachoma. It’s really important,” Hotez said. “Now we’re finding it extends to yaws, scabies and some of the others. So, continuing those programs of preventive treatment for the Mass Drug Administration is a top priority.”
Since the early 2000s, one of the largest global public health programs has involved repurposing low-cost or donated medicines for mass drug administrations aimed at preventing neglected tropical diseases. Hotez named azithromycin, a common antibiotic for strep throat and sinusitis that can also be used for trachoma, as an example. However, efforts to use this drug may be slowed because of the pandemic, he said.
“Essential medicines for neglected tropical diseases often rely on the delivery through volunteer community health workers, or schoolteachers, and the big issue is what happens now with COVID-19 if social distancing is put in place? Will this interrupt those efforts?” he said. “That’s a big concern.”
Additionally, because of the pandemic, many people are either forced to stay at home or fear leaving. Recently, there has been a decrease in U.S. vaccination rates for measles and other diseases because of the pandemic, and Hotez fears it may be worse in smaller, poorer health care systems.
“U.S. childhood vaccinations actually declined by 50% or more in March and April of the COVID-19 pandemic,” he said. “That is in a strong health system. You can imagine in a fragile health system how easy it could be to disrupt that, and that’s one of the things we’re very concerned about.”
- WHO. About the WHO Global Malaria Programme. World Health Organization, 20 May 2020, www.who.int/malaria/about_us/en/. Accessed June 25, 2020.
- Guinea Worm Eradication Program. The Carter Center. www.cartercenter.org/health/guinea_worm/index.html. Accessed June 25, 2020.
- Konopka-Anstadt JL, et al. Vaccines. 2020;doi:10.1038/s41541-020-0176-7.
- Tait DR, et al. N Eng J Med. 2019;doi:10.1056/NEJMoa1909953.
- WHO. The potential impact of health service disruptions on the burden of malaria. https://www.who.int/publications/i/item/the-potential-impact-of-health-service-disruptions-on-the-burden-of-malaria. Accessed July 28, 2020.
- WHO. TB Strategy Guide. https://www.who.int/tb/strategy/End_TB_Strategy.pdf.
- For more information:
- Dennis Falzon, MD, can be reached at email@example.com.
- Peter J. Hotez, MD, PhD, can be reached at firstname.lastname@example.org.
- Kimberly A. Lindblade, PhD, can be reached at email@example.com.
- Walter A. Orenstein, MD, can be reached at firstname.lastname@example.org.
- Adam Weiss, MPH, can be reached at email@example.com.
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