As the CDC and local health administrators prepare for the likely transmission of mosquito-borne Zika in parts of the continental U.S., some public health officials are looking back to the only other outbreak of an epidemic-prone virus linked to adverse outcomes in newborns in recent history — the rubella outbreak of 1964, according to The Atlantic.
Here are five things to know about the rubella outbreak of 1964 and Zika today.
1. Rubella in 1964: In 1964 and 1965, a rubella epidemic sickened more than 10 million people in the United States. Approximately 20,000 infants died from complications associated with rubella and 30,000 more were born with severe birth defects like cataracts, deafness, enlarged spleens, liver problems, bleeding disorders and abnormalities in the bones and bone marrow. A rubella vaccine was made available in 1969. Twenty-three million children were vaccinated within two years. Rubella is now rare in developed nations. Most physicians in the Western Hemisphere will only encounter the disease in textbooks.
2. Zika now: The World Health Organization recently confirmed an international scientific consensus that Zika is indeed connected to the birth defect mircrocephaly, a condition in which babies are born with abnormally small heads, and other neurological disorders like Guillain-Barré syndrome.
3. Similarities: "The similarities are great between rubella and Zika. Both are fever-rash illnesses, and both have arthropathy, or arthritis, as manifestations," Susan Reef, MD, who leads the rubella team in the CDC's Global Immunization Division, told the Atlantic. "Also like rubella, there's an asymptomatic component to Zika, so not everyone knows when they're infected with rubella or with Zika."
4. Differences: Rubella is transmitted via person-to-person contact, while Zika is spread through sexual transmission and mosquitoes. Other differences could be cause for grave concern. Authors of a New England Journal of Medicine study published in March wrote, "A major difference of concern between Zika infections in Brazil [between 2015 and 2016] and rubella virus infections in the U.S. pandemic of [1959 to 1965] is the level of population immunity... [Today], none of the population has antibodies to Zika. In contrast, in the United States during the rubella epidemic, there were 20,000 cases of the congenital rubella syndrome, but in 1959 only 17.5 percent of women of childbearing age lacked rubella antibodies."
5. Pregnancy: Dr. Reef told the Atlantic key areas in the fight against Zika will be coming to a more complete understanding of Zika's clinical manifestations in pregnant women and the lasting nature of the effects in neonates. For researchers to compile knowledge on these subjects in regards to rubella, it took the 1964 epidemic. Health officials today are hoping to learn what they can from history and circumvent a potential modern Zika epidemic. Peggy Honein, PhD, a leading researcher in birth defects on the CDC's Zika Response Team, told the Atlantic, "What we learned about rubella and pregnancy, and how we learned it — we are definitely looking to those lessons as we learn more every day about Zika virus."
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