Travel testing requirements may have only minor impact on COVID spread, Stanford experts say

Aug. 2, 2022, 7:09 p.m.

Stanford experts urge continued precautions amidst rising BA.5-variant COVID-19 cases, despite the CDC’s removal of a testing requirement for international flights on June 10.

COVID-19 cases and hospitalizations are rising nationally from a new subvariant known as BA.5, with concerns of increased transmission due to the changed policy.  However, Stanford experts say the CDC’s policy change does not explain the surge of new cases.

“Removing a testing requirement might theoretically increase the number of COVID cases, but it is only one part of a very complex picture,” Stanford Healthcare immunologist and infectious disease specialist Paul Bollyky wrote in a statement to The Daily.

According to epidemiology and population health professor Julie Parsonnet, the risk of infection at both ends of a flight is so high that a testing requirement would not necessarily prevent the “introduction” of the virus. Although airplanes are “less risky than in other environments” due to “their excellent air circulation,” wearing masks should be required on flights, Parsonnet said. 

“Testing in general also does not lower transmission per se,” Bollyky wrote. “It makes intuitive sense that awareness of one’s COVID status might make a person more likely to behave in ways that reduce transmission to others,” but Bollyky is unaware of any models that have quantified the extent of this. 

“There is so much COVID now that restricting travel would likely have very little impact,” Parsonnet said. She attributed the rise in cases instead to a lack of masking among the public: “It’s like everyone is going out in the pouring rain without raincoats and then wondering why they are wet.” 

Still, the experts maintain the importance of continued precautions against the virus.  Stanford Medicine infectious diseases professor Dean Winslow advised people to keep getting tested in order to protect others. The COVID-19 virus mutates rapidly and has become more transmissible and infectious as new variants emerge – BA.5, the most recent one, spreads more efficiently than previous strains, though it is less deadly, according to Winslow. 

Winslow also said that many vaccinated people’s immunity against COVID-19 has decreased since their last booster dose, possibly increasing the number of cases as well. With rising case numbers and waning immunity, Winslow emphasized the importance of wearing a mask and getting vaccinated.

Parsonnet echoed Winslow’s advice and encouraged people to “pay attention to COVID rates in the communities you visit.” 

Though experts expressed uncertainty about the future of the pandemic, they predicted the virus will continue to mutate and evolve. According to Winslow, COVID-19 will become more like seasonal influenza and it is likely yearly booster shots will be needed. “I think it’s going to be with us for quite some time,” Winslow said.

Aslıhan Alp is a high schooler writing as part of The Daily’s Summer Journalism Workshop. Contact them at workshop 'at' stanforddaily.com.

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