The polio epidemic in the Marshall Islands 57 years ago offers a cautionary note in today’s coronavirus world. A total of 194 Marshallese and two Americans experienced some level of paralysis and 11 Marshallese died on 10 of 22 populated atolls.
The polio epidemic here happened eight years after a vaccine for the polio virus had been invented and was in wide use in the United States and other countries. But the vaccine was not used in Marshall Islands until after the epidemic started at the US Navy base at Kwajalein in January 1963 and quickly spread to the Marshallese community at Ebeye.
In early January that year, a nine-year-old American girl living with her family at what was then the US Navy base at the Pacific Missile Range Facility on Kwajalein developed an illness that included fever, headache, malaise, dizziness and vomiting. On the third day, she developed paralysis related to her spinal chord and was evacuated to Hawaii for treatment. This was the first recognized case of paralytic poliomyelitis in the 1963 epidemic, according to a detailed medical paper published by the American Journal of Epidemiology in 1966.
Five days after paralysis appeared in the American girl, a three-year-old Marshallese boy living on Ebeye was admitted to the Ebeye dispensary with paralysis of the right leg following two days of fever. “His five-year-old cousin and close playmate, who often accompanied his grandmother to work on Kwajalein, became paralyzed on the following day,” said the paper in the medical journal, “Poliomyelitis in an isolated population: Report of a Type 1 Epidemic in the Marshall Islands, 1963.”
“Over the ensuing three days, five additional (Marshallese) children were brought to the dispensary with paralytic illness.”
With assistance of the American medical doctor on Kwajalein, it was determined these were infectious cases. On January 16 — four days after the first Marshallese child was seen with paralysis, and nine days after the American girl developed paralysis — authorities placed a quarantine on travel between Ebeye and Kwajalein, and called for help from a Preventive Medicine Unit at the Pearl Harbor Navy base in Honolulu.
The medical team arrived in three days but already 25 cases of paralysis had occurred on Ebeye among Marshallese, while a second American child had developed paralysis on Kwajalein.
January 19 and 20, the entire populations of Kwajalein and Ebeye were fed the type 1 oral polio vaccine. By January 24, the rate of new cases was slowing.
While polio cases on Ebeye declined quickly in the wake of a vaccine being applied to the entire population, the virus spread to the outer islands through ship visits.
“On January 29, a radio message was received in Kwajalein from the distant atoll of Rongelap stating that emergency medical aid was needed as 16 of the 208 inhabitants had a paralytic disease,” said the medical journal article. “The following day, a physician from the Pacific Missile Range Hospital on Kwajalein was flown by Navy Air-Sea Rescue amphibian plane to this island, where the clinical diagnosis of poliomyelitis was confirmed.” Health officials gave all Rongelap residents the oral polio vaccine during their visit.
“The evidence that the disease had escaped the confines of Kwajalein Atoll, plus the alarming susceptibility of the islanders, resulted in an emergency immunization program for the entire Marshallese population utilizing type 1 oral polio vaccine,” said the medical journal article. “The only deterring factor was the necessary delay in obtaining vaccine.”
Vaccines were initially targeted on all of the islands visited by the field trip ship that had visited Rongelap and was known to be the agent of transmission, since it was the only contact the northern atoll had had with the outside world in two months.
The spread of polio to the outer islands occurred because two Marshalls District field trip vessels — the Mieco Queen and the Ran Annim — left Ebeye for the outer islands before the illness among children on Ebeye was recognized as a polio epidemic. “With efforts directed to control the disease on Ebeye and Kwajalein islands, the Marshallese soon forgot about their departure with healthy adults and children,” said the medical journal article.
The Ran Annim stopped at Rongelap, Wotho, Lae, Ujae and Ujelang before returning to Majuro on January 29. The Mieco Queen, before returning to Majuro, stopped at three islands in Namu Atoll.
The Ran Annim made two more voyages from Majuro before being quarantined. This included a trip from Majuro to Maloelap on February 4, but with no children on board. Children were identified as the primary source of virus spread. Meanwhile, on the same day, the 30-foot sailing vessel Arno Schooner, sailed for three isolated islands in Arno.
Three cases of paralysis from polio had already happened in Majuro when these vessels departed for Maloelap and Arno. After Maloelap, the Ran Annim went to Wotje and Likiep. The vessel was put into quarantine at Likiep on February 10 until immunization of the entire population was completed five days later.
Both Wotho and Maloelap developed no cases polio cases. But people living on Rongelap, Ujae, Lae, Ujelang, Majuro and Arno contracted the virus that started at Kwajalein. One child each on Likiep and Wotje suffered from polio. They had been exposed to the visit of the Ran Annim’s passengers on February 9 and 10, respectively. The vaccine was provided either the same day or one day after possible exposure to the virus on Likiep and Wotje. The fact that the polio vaccine was brought to these two islands on February 10 clearly helped prevent further spread.
Although the 1963 polio epidemic started at Kwajalein and moved to Ebeye, the most cases of paralysis associated with polio occurred in Majuro.
A total of 64 people of the 3,933 then residing in Majuro Atoll suffered from some level of paralytic polio. The number of cases in Majuro was almost exactly one-third of the 194 cases recorded among Marshallese on the 12 islands/atolls that were exposed to polio in 1963.
Ebeye accounted for 56 of the total. Ebeye’s population at the time was 1,971.
The two outer atolls that were hit hardest with polio cases were Ujelang, with 20 cases among 275 people, and Rongelap, with 19 among 208 people. Ujae and Arno both saw 10 cases each, Namu had nine, Lae four and Wotje and Likiep one each.
Over 80 percent of the 194 cases among Marshallese were among children six years of age and younger. “The extraordinary susceptibility of the Marshallese under age seven to paralysis implies a most deficient immune status,” said the medical journal article.
The so-called “attack rate” for polio among the populations living on the infected islands was 22 per thousand people, “many times higher than experienced in major epidemics in the United during the past 10 years,” said the medical journal article published in 1966. But the age specific attack rate for young children was more severe, at 85 per 1,000. By contrast, the attack rate in the American population of 3,000 with two cases was 0.7 per 1,000 in large part because most of the Americans were already immunized against polio.