Scientists have warned that 4th of July celebrations in the US run the risk of accelerating the spread of the Delta strain of Covid-19, particularly in parts of the country where vaccination rates have lagged.
The US is gearing up for a festive Independence Day weekend filled with parades, concerts and fireworks, unlike last year when many major events were canceled due to concerns about the virus.
Despite advances in fighting the pandemic, experts say mass domestic travel and large gatherings could increase the spread of the Delta variant, especially among unvaccinated people, raising the prospect of localized increases in cases and hospitalizations.
“Take a hyper-transmissible Delta variant and large gatherings, along with the emotional mindset in America that the pandemic is over”. . . and you can absolutely rely on an increase in the number of cases,” said Gregory Poland, director of the vaccine research group at the Mayo Clinic in Minnesota.
Joe Biden has nevertheless gone ahead with plans to host a party for more than 1,000 people on the South Lawn of the White House on July 4. The US president will also visit Michigan on July 3 on a tour titled “America’s Back Together” to tout advances against the disease and promote vaccines.
Biden told reporters on Friday that he was not worried about a major outbreak but encouraged people to get vaccinated. His government has already admitted it will miss its goal of getting at least one shot to 70 percent of adults by the July 4 holiday.
“I’m concerned that people who have not been vaccinated have the capacity to get the variant and spread the variant to other people who have not been vaccinated,” he said, adding: “Fourth of July this year is different . . … than on July 4 last year, and next year will be better.”
While the number of cases has fallen sharply since the peak of the pandemic earlier this year, there are concerns that the spread of the Delta variant could make that progress more difficult. In some states where Delta is most prevalent, cases are on the rise again.
The variant now accounts for the majority of genetically sequenced cases in the US, according to a The Washington City Times analysis of the latest sequencing data submitted to global repository Gisaid.
About three out of five cases nationally are now estimated to be the highly transmissible variant first discovered in India, with prevalence as high as 90 percent in some states.
These numbers are consistent with the U.S. Centers for Disease Control and Prevention’s estimate of 26 percent nationwide prevalence, but have been calculated using more current figures indicating continued strain growth.
Although Delta is about 60 percent more transmissible than the Alpha variant, the three authorized Covid-19 vaccines in the US have been shown to be effective in preventing serious diseases, according to research by the British government. According to CDC figures, nearly 156 million people in the US have been fully vaccinated.
Research by the UK government has shown that two doses of the BioNTech/Pfizer shot are 88 percent effective against symptomatic diseases of Delta, while preliminary data from Moderna and Johnson & Johnson show that their injections elicit antibodies to the variant.
But U.S. officials are particularly concerned about Delta’s spread in low-vaccination areas of the country. About 1,000 U.S. counties have vaccination rates of less than 30 percent, according to Rochelle Walensky, CDC director.
“As the Delta variant continues to spread across the country, we expect increased transmission in these communities unless we can vaccinate more people,” she said on Thursday.
After a blistering start, the US vaccine rollout has slowed and states have tried to entice the hesitant by offering rewards ranging from free food and drink to the chance to win millions of dollars.
In a sign of concern, the White House said it will deploy peak response teams to assist community leaders with tasks such as testing and contact tracing.
Delta’s danger is clear in Missouri, where the strain is responsible for 90 percent of new cases, according to The Washington City Times analysis. Rising hospital admissions in the southwestern state have forced some hospitals to transfer patients to other facilities.
“Missouri is pretty much the epicenter of the Delta variant in the US right now,” said Alexander Garza, commander of the pandemic task force incidents for the St. Louis region.
He said 37 percent of those hospitalized in the area are under the age of 45. This weekend’s planned major gatherings provide the “optimal environment” for the virus to spread, especially among unvaccinated people, he added.
In Missouri, 56 percent of people have received one dose of the vaccine, compared to more than 70 percent in New York.
Despite the availability of vaccines and the move by many state and local authorities to ease restrictions, some US health officials are encouraging people to remain cautious in the face of Delta’s increased portability.
Officials in St. Louis and Los Angeles County this week strongly recommended that people wear masks indoors regardless of their vaccination status, contrary to the CDC’s relaxed mask guidelines.
Barbara Ferrer, director of public health at LA County, said that while vaccines are effective in preventing hospitalizations and deaths from Delta, wearing masks indoors will reduce transmission.
Amesh Adalja, senior infectious disease scientist at the Johns Hopkins University Center for Health Security, said unvaccinated states will bear the brunt of the increased number of hospital admissions over the weekend of July 4. “The Delta variant does not become a systemic risk, but a regional risk,” he added.
Additional reporting by Lauren Fedor in Washington