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If already double vaccinated, mixing boosters now recommended

The decision to recommend mixing booster shots between any of the three vaccines approved for use in the US, namely Pfizer, Moderna, and Johnson & Johnson (J&J), is something the world will take note of

The effectiveness of the two-dose vaccine against infection wanes over time A newly discovered mutation of the Delta variant is being investigated in the UK Boosters were allowed, but not urged, for adults of any age at increased risk of infection

Granted the below applies to the US, the decision to recommend having booster shots from any of the three vaccines approved for use in the country, namely Pfizer, Moderna, and Johnson & Johnson (J&J), is something the world will take note of.

On October 221, 2021, the US Centers for Disease Control (CDC) cleared booster shots of  COVID-19 vaccines, giving people the freedom to mix and match any of those three vaccine types.

Earlier, the US Food and Drug Administration also authorized booster doses of the COVID-19 vaccines from those three vaccine manufacturers and said Americans can choose a different shot from their original inoculation as a booster.

About 11.2 million people have so far received a booster dose, according to data from the CDC.

“The availability of these authorized boosters is important for continued protection against COVID-19 disease,” acting FDA Commissioner Janet Woodcock said in a statement.  

The effectiveness of the two-dose vaccine against infection wanes over time, according to data the CDC posted. Some studies show small declines in protection against hospitalization too, mainly for those over the age of 65, the data showed. Itl didn’t specify which vaccine should be used as a booster, leaving it up to doctors to decide on that.

“The evidence shows that all three COVID-19 vaccines authorized in the United States are safe – as demonstrated by the over 400 million vaccine doses already given,” CDC Director Rochelle Walensky said in a statement that embraced the committee’s recommendations. “And, they are all highly effective in reducing the risk of severe disease, hospitalization, and death, even in the midst of the widely circulating Delta variant.”

A newly discovered mutation of the Delta variant is being investigated in the UK amid worries that it could make the virus even more transmissible and undermine COVID-19 vaccines further.

A new and modified version of the Oxford vaccine is being developed to target the Delta coronavirus variant, The Independent reports, in the wake of rising infections in the UK and the highest daily death toll since March.

Early work has been started by members of Professor Dame Sarah Gilbert’s team at the University of Oxford, the same scientists behind the AstraZeneca jab first rolled out in January. 

This comes as scientists warn a new offshoot of the Delta variant will “eventually dominate” in the UK if it is confirmed to be more transmissible than its predecessor. 

Who can take what?

Many countries, including the UK, have backed mix-and-match strategies. The CDC said the data has shortcomings, noting that some recipients may have been engaging in riskier activities after getting vaccinated.

The agency recommended the Moderna booster for elderly people and at-risk adults six months after they complete their primary series of shots.  Moderna recipients can get a booster at half the dosage of the original two shots.

People who initially got J&J’s COVID-19 vaccine had a stronger immune response when boosted with either the Pfizer or Moderna shot, showing that “mixing and matching” booster shots of different types was safe in adults.

Starting six months past their last Pfizer or Moderna vaccination, people are urged to get a booster if they’re 65 or older, nursing home residents, or at least 50 and at increased risk of severe disease because of health problems. Boosters also were allowed, but not urged, for adults of any age at increased risk of infection because of health problems or their jobs or living conditions. That includes healthcare workers, teachers, and people in jails or homeless shelters.

As for recipients of the single-shot J&J vaccine, a COVID-19 booster is recommended for everyone at least two months after their vaccination. That’s because the J&J vaccine hasn’t proved as protective as the two-dose Moderna or Pfizer options.

Booster risks

CDC official Dr. Tom Shimabukuro presented data that showed there is an increased risk of rare inflammatory heart conditions, myocarditis, and pericarditis, following vaccination with the Moderna or Pfizer vaccine, particularly following the second dose.

The rate of the rare heart conditions within seven days of vaccination was 10 cases per million doses, Shimabukuro said, citing a study of U.S. military members. It often occurred in young men and usually after the second dose, he said. Most patients reported feeling fully recovered within six weeks.

The surveillance is “ongoing,” he said.