On October 7th, 2023, as the world watched in shock at the unfolding violence between Hamas and Israel, a less visible yet equally insidious threat was emerging in Gaza: polio. The sudden eruption of armed conflict not only devastated lives and infrastructure but also set the stage for a public health crisis that had been brewing silently in the background. The renewed hostilities between Israel and Palestine led to severe disruptions in healthcare services and humanitarian aid, creating conditions in which diseases like polio could thrive once again.
Poliomyelitis, commonly known as polio, is a highly infectious viral disease that primarily affects children under the age of ten, leading to paralysis, and in more severe cases, death. In the early 20th century, the spread of polio was one of the primary public health concerns, causing widespread fear due to its rapid transmission and severe consequences. “When I was a kid, I and countless other kids in New York went to camp or entire families left the city because of the fear of polio in the summer spreading around public swimming pools,” said Dr. Michael Weitzman, former director of the Center for Child Health Research and former chairman of the Department of Pediatrics at New York University’s School of Medicine.
The quest for a vaccine culminated in 1955 when Dr. Jonas Salk, an American physician and researcher, announced the successful development of the first effective polio vaccine. This inactivated poliovirus vaccine (IPV) employed a killed version of the virus to stimulate immunity without infecting patients. Famously, and quite remarkably, Salk chose not to patent the vaccine – a decision that ensured the vaccine’s widespread accessibility which significantly reduced the global incidence of polio.
Following Salk’s medical breakthrough, Dr. Albert Sabin developed an oral poliovirus vaccine (OPV) in the late 1950s. This live-attenuated vaccine (meaning that the vaccine contained an alive but altered version of the virus to provoke an immune response), was easier to administer, facilitating mass vaccination campaigns around the globe, especially in regions with limited medical infrastructure. The OPV became, and is still the cornerstone of global polio eradication efforts, contributing to a 99% decrease in polio cases worldwide since the 1980s. “Vaccination is really the great weapon against infectious diseases like polio,” said Weitzman. “Any place where you don’t have herd immunity and ongoing immunization against this will place people at risk.”
The Gaza Strip, a densely populated region with a notably complex social and political history, has experienced fluctuations in the incidence of polio over the past few decades. However, despite the challenges posed by political instability and economic hardship, the health authorities in Gaza, in collaboration with international organizations like the World Health Organization (WHO) and the Global Polio Eradication Initiative (GPEI), maintained relatively robust vaccination programs. In the late 20th century, concerted vaccination campaigns were implemented in Gaza, leading to the successful eradication of polio by 1999. This high vaccination coverage, with rates reaching close to 99%, were instrumental in keeping polio at bay for close to two decades.
“This new outbreak is an unintended but unavoidable consequence of the war, which is why it is so devastating on multiple levels,” said Weitzman. The violent escalation following the October 7th attacks on Israel marked a devastating turning point in Gaza’s efforts to manage public health. The conflict exacerbated existing vulnerabilities in the region’s healthcare system, already weakened by years of blockade and resource scarcity. Decisions made by the Israeli government to block essential supplies from reaching Gaza have disrupted routine immunization programs that had maintained essential vaccine coverage. Additionally, the Israeli Air Force’s aerial bombardment campaign on Gaza has wreaked havoc on existing civilian infrastructure, making it almost impossible to maintain vaccination efforts. According to the United Nations, as of September 30, 2024, sixty-six percent of the total structures in the Gaza Strip have been damaged in the conflict.
In the wake of this destruction, vaccine rates dropped below ninety percent for the first time in over a decade. This decrease in immunization combined with the destruction of vital civilian infrastructure and the displacement of thousands of people made it once again possible for polio to reemerge.
The strain of polio circulating in Gaza has been traced to Egypt, where a weakened form of the virus used in oral vaccines mutated and regained the ability to cause disease. The oral polio vaccine is highly effective and safe, but in rare cases, the weakened virus can mutate after being excreted and become virulent again. This occurred in Egypt in 2023 and the virus spread to Gaza through human interactions between the two regions. Given the high transmissibility of polio and the dense, unsanitary conditions in Gaza, the situation escalated quickly once routine vaccination efforts were interrupted by the conflict.
In August of 2024, an infant was diagnosed with partial paralysis due to the virus, marking the first case of polio in Gaza since the outbreak of the war. Subsequent testing revealed dangerous levels of the virus in the wastewater in Gaza. With sewage systems destroyed as a result of the war, civilian exposure to wastewater became more common, likely starting the outbreak.
The Response
The oral vaccine, while effective, requires two doses to ensure full protection, presenting a massive logistical challenge to healthcare workers attempting to provide full coverage to the more than 500,000 children in Gaza. Health workers have faced significant obstacles due to the ongoing violence, with airstrikes contributing difficulty to certain operations. Humanitarian pauses in the fighting were critical to completing the first phase of vaccinations, and similar pauses are planned for the second phase. Without these pauses, it would have been impossible to reach children across Gaza, where the densely packed population and damaged infrastructure present logistical nightmares for vaccination efforts.
Fortunately, the response to the outbreak was swift, and by most standards effective, though there certainly remains more to be done. The vaccination campaign, organized by the WHO, UNICEF, and the United Nations Relief and Works Agency (UNRWA), in conjunction with local health officials achieved remarkable response under difficult circumstances. In the second round of the campaign that wrapped up in early November 2024, the WHO reports that a total number of 556,774 children under ten years old received the second does of the polio vaccine.
According to the WHO, currently, the campaign has reached ninety-four percent of its target population. Regionally the campaign saw overwhelming success in central and southern Gaza reaching vaccination coverage rates in the high nineties. However, in northern Gaza where access to healthcare providers was severely limited due to intense bombardments with few humanitarian pauses, coverage remained lower at eighty-eight percent.
Efforts to contain the virus will continue over the coming months, with health officials monitoring the wastewater and population in Gaza for signs of polio circulation. Given the immense challenges posed by war, displacement, and poor sanitation, the polio vaccination campaign is just one part of a much broader public health struggle in Gaza. Health workers and humanitarian agencies remain on high alert as they work to prevent worsening conditions in an already devastated region.
“This really shows the importance of vaccination,” said Weitzman. “If we don’t continue to vaccinate people at current rates and increase rates in some parts of the world, I think we will see infectious disease from the past recur.”
The stakes for the Gaza polio vaccination campaign could not be higher. With thousands of children relying on these critical immunization programs and sanitation infrastructure in dire need of repair, the situation highlights the challenges of providing healthcare services in conflict zones.
At this point in time, it does seem like the only permanent solution is the prolonged cessation of violence. “Yes, we can restrict it [polio] while the war is going on, but that doesn’t mean something else won’t happen – people will continue to be malnourished and displaced, which makes them at risk for other diseases or problems,” said Weitzman.
As humanitarian organizations continue to push forward with vaccination campaigns, the outcomes may determine more than just the future of polio in Gaza — this could help set a new precedent for addressing healthcare needs in regions devastated by conflict.
“This really shows the importance of vaccination,” said Dr. Michael Weitzman, former director of the Center for Child Health Research and former chairman of the Department of Pediatrics at New York University’s School of Medicine. “If we don’t continue to vaccinate people at current rates and increase rates in some parts of the world, I think we will see infectious disease from the past recur.”