The CDC now considers delta a “variant of concern.”
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The coronavirus is, unfortunately for us, good at doing what viruses do best: mutating in order to become more efficient and infect more people. The newest mutation to cause concern is the delta variant, the strain first documented in India, which has since caused devastation in the country.

Delta’s growth across the globe has recently caused some countries in the Asia-Pacific region to reimpose lockdowns and other restrictions governments had lifted, The New York Times reported Tuesday. Notably, COVID outbreaks in Australia, fueled by delta, have forced the cities of Sydney, Perth, Brisbane and Darwin back into strict lockdowns.

At the end of May, the World Health Organization renamed coronavirus variants of concern with letters of the Greek alphabet. The so-called delta variant has moved from merely being identified in the US to accounting for more than 20% of COVID cases, Dr. Anthony Fauci, the president’s chief medical advisor, said on June 22 at a White House press briefing. The number of COVID cases caused by delta are doubling every two weeks in the US, Fauci said.

The US is fortunate to have great vaccine availability, and 66.1% of the adult population has received at least one dose of a COVID-19 vaccine, according to June 28 data from the Centers for Disease Control and Prevention. But even with an increasing number of people vaccinated against COVID-19, the delta variant’s appearance in the US is concerning.

The strain is about 60% more transmissible than the alpha variant (a strain first documented in the UK), British epidemiologist Neil Ferguson told reporters, and it’s suspected to carry the potential for more severe disease. In a Scottish study published on June 14, researchers found that, compared to the alpha variant, delta doubled the risk of hospitalization.

Experts in the US worry that the delta variant will follow the course it took in the UK — start off small, but eventually become the dominant strain in the country. In an interview with CNN on June 18, Dr. Rochelle Walensky, director of the US Centers for Disease Control and Prevention, said that she anticipates delta will be the “predominant variant in the months ahead.”

The three vaccines available in the US have all proved to have excellent efficacy against severe disease caused by COVID-19. But how do they fare against the more contagious variant? Some research is promising, and scientists still urge vaccination as the way out of this deadly pandemic.

Delta’s side effects

In mild cases, the delta variant may show up a little differently. Tim Spector, British epidemiologist and co-founder of the ZOE COVID Symptom study in the UK, says that since May, the app has been recording different top symptoms of COVID-19. He says the No. 1 symptom of COVID-19 is now a headache, followed by sore throat, runny nose and fever — not the more “classic” COVID symptoms. Coughing is now the fifth-reported symptom.

“We don’t even see loss of smell coming into the top 10 anymore,” he says. “This variant seems to be working slightly differently.”

Spector says these changes — which appear to be linked to the delta variant — may cause people to continue going out, thinking they have a common cold instead of COVID-19.

News of COVID-19 causing a black fungus in the sinuses and brain and hearing loss, among other serious symptoms, in COVID-19 patients from India may be alarming and lead you to believe delta causes new and scarier side effects than older strains of the coronavirus. The reality is COVID-19 from all strains and forms is a formidable disease, with a myriad of side effects that can last months after infection in some people. As Business Insider reported, there isn’t enough data at this time to support that the delta variant causes these atypical COVID-19 symptoms.

The WHO labels “variants of concern” and “variants of interest” using letters of the Greek alphabet. Variants of concern — delta included — means they have been associated with either an increase of transmissibility, increase in virulence or change in clinical presentation, and/or decrease in effectiveness of public health measures, according to the WHO.
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How Pfizer, Moderna and J&J compare

Research from late May by the UK body Public Health England found that two doses of Pfizer’s or AstraZeneca’s COVID-19 vaccine are effective against the delta variant — about 88% (Pfizer) and 60% (AstraZeneca). Although this study shows that two doses are about 5 and 6 percentage points less effective, respectively, with the delta variant than the alpha strain, the study also found that both vaccines had about 33.5% effectiveness against delta after one dose of either AstraZeneca or Pfizer — considerably less protection than two doses of either vaccine.

This study may also suggest some promise for another vaccine being used in the US: Moderna. Although it wasn’t used in this study because the vaccine hasn’t been widely used in the UK, Moderna and Pfizer are both mRNA vaccines and have similar reported efficacy rates.

The Scottish study published June 14 also confirms Pfizer and AstraZeneca’s effectiveness against infection from the delta variant. Researchers from this study say AstraZeneca had 60% protection two weeks after the second dose, while Pfizer had 79% protection two weeks after the second dose.

As far as Johnson & Johnson (the US’s single-dose vaccine) is concerned, research isn’t as clear or as available. Some experts, including Stanford professor Dr. Michael Lin, say that those who got a J&J single-dose vaccine may need a booster sooner than their Pfizer or Moderna-receiving counterparts, and that J&J might be less effective than Pfizer or Moderna when faced with the delta variant. On Twitter, Lin said that while the CDC may be waiting before making an official booster call, receiving an mRNA vaccine after getting the Johnson & Johnson will likely be safe, and pointed out a study done in Spain that suggests benefits to mixing Pfizer and AstraZeneca vaccines. (AstraZeneca is a viral vector vaccine, like Johnson & Johnson.)

That’s not to say Johnson & Johnson definitely offers less protection against delta. According to a study published in the Nature journal, the Johnson & Johnson vaccine had less antibody response when faced with coronavirus variants (not delta), but T-cell responses were “largely preserved.” As NPR reported, T-cell responses don’t stop an infection, but they stop it from spreading — this matters when talking about a vaccine’s main purpose and effectiveness against severe disease.

Moving forward

The expert advice does not seem to change as the coronavirus does — getting vaccinated and gaining immunity against COVID-19 is the surest way to prevent severe disease caused by any variant. With fewer people getting infected with COVID-19, the coronavirus has less room and fewer hosts within which it can mutate.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.