Health

Covid vaccine: Studies suggest giving a single shot to more people


Three new studies suggest that as many people as possible should receive at least one dose of the coronavirus vaccine. 

Currently, both vaccines approved for emergency use authorization in the U.S. – from Pfizer Inc and Moderna Inc – require two doses administered about one month apart.

But researchers from Yale University, Stanford University and the University of Washington have found that an initial dose is about 50 percent effective at preventing COVID-19 infection.

This could help curb the spread of the virus and help relieve hospital systems from some of the strain they are under – and then second doses could be given a few months later. 

It comes as the new threat of ‘super-covid’ variants arises in the U.S., where at least 10 people have the variation that has triggered a third wave of lockdowns in the UK. 

The new strain, known as B 1.1.1.7., has been identified in at least 30 countries and another from South Africa is in the UK and at least seven other nations.

Experts believe vaccines will likely work against both variants  – but at this rate, these more infectious mutant forms could easily outpace the U.S. vaccination effort if they become widespread.  

Studies from Yale University and the University of Washington found that one dose of the coronavirus vaccine (yellow and blue lines) is about 50% effective, which could help reduce the number of infections

Studies from Yale University and the University of Washington found that one dose of the coronavirus vaccine (yellow and blue lines) is about 50% effective, which could help reduce the number of infections

Another study, from Stanford University found that giving as many as people as possible a first dose, known as a 'flexible strategy,' could reduce an additional 23% to 29% of COVID-19 cases (above)

Another study, from Stanford University found that giving as many as people as possible a first dose, known as a ‘flexible strategy,’ could reduce an additional 23% to 29% of COVID-19 cases (above)

The rollout of coronavirus vaccines has been much slower than expected with only 4.5 million people across the U.S. receiving their first dose out of 15 million distributed doses, according to the Centers for Disease Control and Prevention.

That figure is well short of the 20 million people the Trump administration had hoped to immunize by New Year’s Eve. 

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The trio of new research, published in the Annals of Internal Medicine, suggest giving as many Americans as possible one dose of the COVID-19 vaccine before distributing the second dose could ‘maximize population health benefits.’

In one study, conducted by Stanford University, researchers developed a model to test different vaccine distribution methods. 

The first model, known as the ‘fixed strategy,’ gives 50 percent of patients their first doses and reserved the other 50 percent for the second dose three weeks later.

The second model, known as the ‘flexible strategy,’ reserves 10 percent of the supply for second doses during the first three weeks, 90 percent during each of the next three weeks, and 50 percent thereafter.

Results showed the flexible strategy would result in preventing between 23 percent and 29 percent of cases COVID-19.

In both scenarios, 24 million people received at least one dose of the vaccine by week eight.

However, in the flexible strategy resulted in 2.4 million additional people receiving two doses because one million more people had been given an initial dose during the first three week compared to the other strategy.

‘We find that under most plausible scenarios, a more balanced approach that withholds fewer doses during early distribution in order to vaccinate more people as soon as possible could substantially increase the benefits of vaccines, while enabling most recipients to receive second doses on schedule,’ the authors wrote.  

In another study, from Yale University, the team developed a model analyzing coronavirus transmission and vaccination leading to protective immunity.

Consistent with the Food and Drug Administration (FDA), researchers assumed the two-dose vaccine would prevent the risk of contracting the coronavirus by 95 percent and took four weeks to achieve lifetime protection.

This was compared with two hypothetical, single-dose alternatives, one with lifetime protection and the other with protection for about six months.

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The model showed that a single-dose with six months of protection would need to be 75 percent effective to prevent as many infections as a two-dose vaccine with 95 percent efficacy.

However, a single-dose vaccine conferring lifetime protection would only need to be about 55 percent effective to avert as many infections as the two-dose jab. 

Researchers also argue that it is more cost effective to distribute the first doses because it would relieve the burden on strained health care systems

Researchers also argue that it is more cost effective to distribute the first doses because it would relieve the burden on strained health care systems

The vaccine rollout in the U.S. has been very slow, with just 4.5 million people receiving shots, short of the 20 million the Trump administration hoped for. Pictured: A staff member at Hamilton Park Nursing and Rehabilitation in Brooklyn, New York, receives the Pfizer-BioNTech coronavirus vaccine from Walgreens Pharmacist Craig Brandt, January 4

The vaccine rollout in the U.S. has been very slow, with just 4.5 million people receiving shots, short of the 20 million the Trump administration hoped for. Pictured: A staff member at Hamilton Park Nursing and Rehabilitation in Brooklyn, New York, receives the Pfizer-BioNTech coronavirus vaccine from Walgreens Pharmacist Craig Brandt, January 4

‘The success of a COVID-19 vaccination program will depend more on the speed and reach of its implementation than on the efficacy of the vaccine itself,’ the authors wrote.

‘Depending on the duration of protection conferred, a single-dose vaccine with 55% effectiveness may confer greater population benefit than a 95%-effective vaccine requiring two doses.’

The third article, an editorial, from a team at the University of Washington and Fred Hutchinson Cancer Research Center, analyzed data from the clinical trials run by Pfizer-BioNTech and Moderna.

A single dose of the Pfizer-BioNTech shot was found to be 52 percent effective at preventing COVID-19 infection.

Meanwhile, the Moderna jab was reported to be 51 percent effective in the first 14 days after the first dose.

Additionally, a single dose of the Moderna vaccine decreased the number of asymptomatic coronavirus infections by two-thirds.

Based on these findings, they suggest that speed of the vaccine rollout is essential for controlling the COVID-19 pandemic rather than administering two doses.

‘Doubling the vaccine coverage with a single dose compared with a two-dose regimen will accelerate pandemic control because even lack of complete protection on an individual level is likely to lower transmission rates enough to stop epidemic growth,’ they wrote.   

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‘Providing effective protection for as many people as possible is more ethical because it distributes the scarce commodity more justly.’

Former FDA Commissioner Dr Scott Gottlieb said on CNBC on Monday (above) that the government should change its current policy of withholding about half of the available supply to making sure everyone gets at least one shot

Former FDA Commissioner Dr Scott Gottlieb said on CNBC on Monday (above) that the government should change its current policy of withholding about half of the available supply to making sure everyone gets at least one shot 

The researchers also noted that more adverse events, such as fever, headache, fatigue and chills, were reported within seven days of people receiving the second dose compared to the first dose.

‘A single-dose vaccine approach could mitigate the higher incidence of many vaccine-associated adverse events seen with the second vaccine dose, increasing tolerability and thus likely acceptability in the general population,’ they wrote. 

The studies come on the heels of former FDA commissioner Dr Scott Gottleib suggesting the U.S. should expand those eligible to receive the coronavirus.

The government’s current policy is to withhold about half of the available supply to ensure people receive a second dose.

However, with infections rising in several states and many hospital systems at their breaking points, Gottlieb said officials need to prioritize making sure as many Americans as possible receive at least one dose.

‘I think people should be getting the second dose,’ he told CNBC’s Squawk Box on Monday.

‘They should be getting the second dose largely on time, but we can be pushing out more first doses now and using the future supply that’s going to come onto the market in January to administer some of those second doses,’  

‘Right now, every shot in an arm is a win.’



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