Should You Be Worried About Outdoor Transmission During the BA.5 Surge?

7 月 18, 2022World News

BA.5—the omicron subvariant that emerged in South Africa in February before sweeping across the world—is now the dominant coronavirus variant in the United States. Thanks to a unique cluster of mutations on the spike protein, the part of the virus that latches to our cells, BA.5 is believed to be the most contagious strain of SARS-CoV-2, the virus that causes COVID-19, so far.

And it has been able to spread fast. According to the Centers for Disease Control and Prevention (CDC), the subvariant is causing approximately 65% of the country’s COVID-19 cases at the time of publication.

It’s no surprise, then, that more and more stories have emerged of people speculating that they caught COVID-19 outside, which can be a bit unsettling to hear as cases continue to rise in many parts of the country. The outdoors were originally believed to be the safest setting for social gatherings at the height of the pandemic, but you may be wondering if that’s still the case with BA.5. Ahead, experts explain what you need to know about this subvariant, outdoor transmission, and staying safe as you enjoy your summer.

Back up: Why is BA.5 such a big deal right now?

BA.5 caught the attention of public health experts after it quickly displaced the very transmissible BA.1 and BA.2 omicron subvariants. Though the BA.5 wave hasn’t caused a significant spike in hospitalizations or deaths in South Africa, certain locations hit by BA.5, like Portugal, have seen an uptick in hospitalizations. Upon taking a closer look at the new subvariant, scientists discovered that BA.5 has mutations in the spike protein that may allow it to evade the immune system’s first line of defense—antibodies—raising the likelihood that it’ll cause a new wave of infections and reinfections, especially in people with low or waning immunity.

However, early evidence suggests that the vast majority of people with some immunity, either from prior COVID infection or vaccination, will continue to be protected from severe illness, according to preliminary research. Data from South Africa found that two doses of the vaccine provided up to 87% of protection against hospitalization with BA.5, as Bloomberg reported. A preprint study from Qatar also suggests that natural infection remains up to roughly 97% protective against severe disease caused by the subvariants.

So should you be worried about outdoor transmission as BA.5 surges?

Experts say outdoor transmission has always been a thing—with alpha, delta, omicron, and now BA.5. “Yes, you can catch BA.5 outside, but it’s more likely that you’ll catch it indoors than outdoors. This was true for the other variants too,” Linsey Marr, PhD, a professor of civil and environmental engineering at Virginia Tech who studies viral transmission, tells SELF.

Outdoor activities are inherently safer than indoor gatherings, Dr. Marr says. But BA.5’s heightened transmissibility will ultimately lead to more indoor and outdoor spread. “It appears that outdoor transmission has become more likely with the newer variants over the past year (i.e., since delta) as they have become more transmissible, but outdoors remains a much lower-risk setting than indoors,” Dr. Marr explains.

Viral particles disperse more quickly outside, thanks to wind speed and air currents. But the same factors that make indoor settings risky—crowded spaces, poor air circulation, the sharing of food and drink—can also increase your chances of contracting COVID outside. So attending a tightly packed outdoor concert and sharing your drink with a friend tends to lend itself to a higher transmission risk than, say, a park picnic in an open space with a couple of friends who aren’t sitting close to you.

Rodney E. Rohde, PhD, a virologist and professor of clinical laboratory science at Texas State University, tells SELF that many people have seen the outdoors as a “get out of jail free card”—but that has never really been the case. “It’s all about how close you are to that person coupled with airflow [turnover] and ventilation of the space you are in, whether that is indoors or outdoors,” Dr. Rohde says.

Research suggests that outdoor transmission, when it does occur, typically results from prolonged close contact. A computer modeling study conducted in 2021 found that certain conditions—like wind speed and direction and cool, moist ground temperatures—play an important role in airborne transmission. “Wind is typically good because it will lead to more rapid dilution [of particles], but you should pay attention to wind direction and avoid being close and directly downwind of others,” Dr. Marr says.

How to stay COVID safe this summer

Dr. Rohde says nothing has fundamentally changed after omicron, except for people’s general attitudes about the pandemic. The same tried-and-true measures that have been encouraged since 2020—washing your hands often, wearing a high-quality mask, testing regularly, and staying up to date with boosters—still work to curb the spread of COVID-19.

Outdoor spaces, though they aren’t 100% risk-free, remain the safest environments to socialize in, according to Dr. Rohde. Once you head inside, especially in packed areas with low air turnover, there tends to be high transmission of the virus, so plan accordingly. “Masking in those environments, distancing, and vaccination are still effective preventative tools for us to utilize,” Dr. Rohde says.

 

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