COVID SCIENCE-People with allergic reaction to mRNA vaccines can get 2nd dose; Delta variant may be 1,000 times more infectious

By Nancy Lapid

July 26 (Reuters) - The following is a roundup of some of the latest scientific studies on the novel coronavirus and efforts to find treatments and vaccines for COVID-19.

Most with allergy to first mRNA shot can get second dose

Most people with allergic reactions to the first dose of an mRNA COVID-19 vaccine from either Pfizer/BioNTech or Moderna can safely receive the second dose, a new study shows. The rates of allergic reactions to these vaccines have been reported to be as high as 2%, with anaphylaxis, the most serious kind, occurring in up to 2.5 of every 10,000 vaccine recipients, the researchers said. They reviewed data on 189 adults with first-dose reactions to one of these vaccines, such as flushing, dizziness or lightheadedness, tingling, throat tightness, hives, and wheezing or shortness of breath. Most of these adults - 84% - received the second dose of the vaccine, with about a third taking an antihistamine beforehand. All of them tolerated the second dose, including those with first-dose anaphylactic reactions. Any potentially allergic symptoms that developed after the second dose were mild and easily controlled, the researchers reported on Monday in JAMA Internal Medicine https://bit.ly/3iSeJLI. "Complete two-dose vaccination has become even more important with the Delta variant and we suspect there are many more people who did not get their second shot because of allergic symptoms," said coauthor Dr. Matthew Krantz from Vanderbilt University. "Our data suggest that most patients with immediate and potentially allergic reactions to mRNA COVID-19 vaccines tolerate a second dose," his team concluded.

Delta may be 1,000 times more infectious than original virus

The Delta variant of the coronavirus may be over a thousand times more infectious than the original version first identified in Wuhan, China, a Chinese study suggests. Tracking a recent outbreak, researchers found people infected with the Delta variant carry 1,260 times more virus in their noses compared to those infected in the first wave of the pandemic. The higher load means the virus spreads far more easily from person to person, increasing infections and hospitalizations, they reported ahead of peer review in a paper first posted on medRxiv earlier in July and updated on Friday https://bit.ly/3iNDQPR. The interval between when people were exposed to infected individuals and when they themselves were diagnosed decreased from an average of 6 days in 2020 to 4 days during the Delta outbreak, the researchers found. The Delta variant is "outcompeting all other viruses because it just spreads so much more efficiently," said Shane Crotty of the La Jolla Institute for Immunology in San Diego, who was not involved in the Chinese study. In the United States, Delta accounts for about 83% of new infections, with unvaccinated people representing nearly 97% of severe cases.

Popular antacids not linked to severe COVID-19 outcomes

Widely-used antacid medications known as proton pump inhibitors (PPIs) are not linked with severe COVID-19 outcomes, a new study found. Researchers with the U.S. Veterans Affairs Health Care System analyzed data on nearly 15,000 veterans with positive COVID-19 tests, about 42% of whom were using PPIs such as Procter & Gamble's Prilosec (omeprazole), Takeda Pharmaceuticals' Prevacid (lansoprazole), and AstraZeneca's Nexium (esomeprazole). After taking patients' underlying COVID-19 risk factors into account, the risk of becoming sick enough to need mechanical ventilation or to die within two months of diagnosis was no different between regular PPI users and non-users, the researchers reported on Sunday on medRxiv https://bit.ly/2UQdh4H ahead of peer review. "With respect to COVID-19," the researchers concluded, "patients and providers should feel safe to continue to use PPIs at the lowest effective dose for approved indications."

Click for a Reuters graphic https://tmsnrt.rs/3c7R3Bl on vaccines in development.

(Reporting by Nancy Lapid and Julie Steenhuysen; Editing by Bill Berkrot)