6-Month Vaccines: What You Should Know
Mixing Covid Jabs Has Good Immune Response, Study Finds
A mix-and-match approach to Covid vaccines - using different brands for first and second doses - appears to give good protection against the pandemic virus, a UK study has found.
All combinations worked well, priming the immune system.
This knowledge could offer flexibility for vaccine rollout, say experts.
The trial results also hint that people who have already received two doses of AstraZeneca vaccine could have a stronger immune response if they were given a different jab as a booster if recommended in the autumn.
The UK's deputy chief medical officer, Prof Jonathan Van-Tam, said there was no reason to change the current successful same dose vaccine schedules in the UK, however, given vaccines were in good supply and saving lives.
But he says it might be something to look at in the future: "Mixing doses could provide us with even greater flexibility for a booster programme, while also supporting countries who have further to go with their vaccine rollouts, and who may be experiencing supply difficulties."
Some countries are already using mixed doses. Spain and Germany are offering the Pfizer or Moderna mRNA vaccines as a second dose to younger people who have already received a first dose of the AstraZeneca vaccine, following concerns about rare but serious blood clots, rather than about efficacy.
Two doses are important to give the fullest protection and teach the body to make antibodies and T cells to block and kill Covid.
The Com-Cov study, which looked at giving the doses four weeks apart in 850 volunteers aged 50 and above, found:
Lead investigator Prof Matthew Snape, from the University of Oxford, said the findings did not undermine the UK policy of giving people the same jab twice: "We already know that both standard schedules are very effective against severe disease and hospitalisations, including against the Delta variant when given at eight to 12 weeks apart."
He said the new results showed mixed dose schedules were also effective, even though the interval of four weeks studied was shorter than the eight to 12-week schedule most commonly used in the UK.
"This longer interval is known to result in a better immune response," he added.
Mixed dose trial results for a 12-week jab interval will be available next month.
Autumn booster dose?
Meanwhile, another pre-print study, which also came out on Monday, suggests a third dose of AZ vaccine, given more than six months after the second, boosts the immune system.
But experts say it is too early to know if people will need a booster dose this year ahead of winter. It is unclear yet how much immunity might wane over time.
Prof Paul Hunter from the University of East Anglia said: "The big question at present is whether or not we will be being offered booster vaccines in the autumn. With the evidence available from this and other sources, I suspect that will be likely for those most at risk from the virus, either due to age or being clinically vulnerable."
He suggested people who have had a first course of AstraZeneca might be offered the Pfizer vaccine in as a booster rather than a repeat AstraZeneca, while people who had a Pfizer first course may not need an autumn booster, based on the evidence from the Com-Cov trial.
The initial results of this mix and match vaccine trial are highly encouraging and throw up some interesting options for booster doses.
Mixing first and second doses of the Oxford-AstraZeneca and Pfizer-BioNTech vaccines yielded strong immune responses. Indeed, every combination of dosing - Pfizer/Pfizer, AZ/Pfizer or Pfizer/AZ produced higher antibody and cellular responses than AZ/AZ.
Does this mean that two doses of AstraZeneca is somehow inferior? Not necessarily.
It is worth remembering that two doses of AZ are already proven to reduce the chances of being hospitalised with Covid by more than 90%.
So we know from real world evidence that the AZ vaccine is highly effective. The AZ vaccine is a 'slow burner', and immunity levels build over time, especially when the dosing period is stretched. Currently the gap between first and second doses is between eight and 12 weeks which should give a better immune response.
What this trial suggests is that for the third, booster doses, it may be preferable to give a different brand of vaccine than the one used for the first two shots.
But it's also worth noting that mixing vaccines does produce more short-term side effects such as chills, headaches and muscle pain.
'Mix and match' UK Covid vaccine trial expanded
Mixing Covid jabs grows cases of mild side-effects
'Mix And Match' UK Covid Vaccine Trial Expanded
Over-50s who have had a dose of the Pfizer or AstraZeneca vaccine can take part in a study on mixing jabs
A major UK trial looking at whether Covid vaccines can be mixed with different types of jabs used for first and second doses is being expanded.
Combining vaccines might give broader, longer-lasting immunity against the virus and new variants of it, and offer more flexibility to vaccine rollout.
Adults over 50 who have had a first dose of Pfizer or AstraZeneca can apply to take part in the Com-Cov study.
Their second dose could be the same again, or a shot of Moderna or Novavax.
Chief investigator on the trial Prof Matthew Snape, from the Oxford Vaccine Group, said he hoped to recruit 1,050 volunteers who had already received one dose on the NHS in the past eight to 12 weeks.
More than 800 people are already taking part in the research and have received two doses of either Pfizer, AstraZeneca or a mix.
Results of this first stage are expected next month and the expanded trial should have some reportable findings by June or July - although the study will run for a year.
Health experts generally agree that the mixing and matching of the vaccines should be safe. The trial will check for any side-effects or unwanted reactions.
Participants will have blood taken to check how well the vaccines trigger an immune response - in the form of antibodies and T cells - to combat Covid.
Meanwhile, a scientist advising the government has said a lot of experts are "very concerned" after a cluster of cases of the South African coronavirus variant were found in London.
Surge testing is available in Lambeth and Wandsworth after 44 confirmed cases and 30 more probable cases in those areas, according to the Department of Health.
NHS Test and Trace is also providing additional testing in a targeted area within SE16 in Southwark, where a case linked to the other cluster has been identified.
Prof Peter Openshaw, a member of the Covid-19 clinical information network, told the BBC's Newsnight: "I think we're all just hoping that the staged reduction in lockdown is going to be OK.
"If we get rapid spread of the South African or other more resistant variants, it may well be that we are going to have to put the reductions of lockdown into reverse."
Speaking on BBC Radio 4's Today programme, Prof Snape said the option to mix vaccines would "massively increase the flexibility and resilience of the immunisation programme and it will mean we can roll these vaccines out more quickly, not just in the UK but internationally".
He said the "starting point" was to see if a combination of vaccines were "as good in terms of their immune responses", but that there were also "some hints" that a combination might give a better immune response overall.
Earlier, Prof Snape said: "What I'm hoping is that we won't rule out any combinations. That's how we need to look at it: Are there any combinations we shouldn't be giving, because they don't generate a good immune response?"
In other developments:
So far more than 32 million people in the UK have received the first dose of a coronavirus vaccine, while 7.8 million people had both doses.
Outside of the trial, people should still receive the same type of Covid-19 vaccine for their first and second doses, although they can be given different brands if the same vaccine is not available.
The Moderna vaccine is already approved for use in the UK and works in a similar way to the Pfizer/BioNTech one, using a small amount of genetic code from coronavirus to teach the body how to fight off infection.
The Oxford-AstraZeneca vaccine is slightly different and uses a harmless, modified virus to carry instructions on how to beat Covid.
The Novavax jab has not been approved yet in the UK, but is expected to be soon, since trials show it is safe and effective.
It uses proteins from coronavirus that can train the immune system without causing infection.
The UK is not the only country considering using mixed dosing.
Head of China's Center for Disease Control and Prevention, George Gao, recently said China should consider it to boost vaccine effectiveness.
Russia's Sputnik V vaccine involves using two slightly different doses to give immunity.
Prof Jeremy Brown, a member of the UK's Joint Committee of Vaccination and Immunisation, which advises on vaccines, said in coming years people will eventually "have to" have a mix of Covid-19 jabs.
He told the BBC: "It's practically going to have to be that way because, once you've completed a course of, say, the Moderna or Pfizer or the AstraZeneca, with two doses - in the future, it's going to be quite difficult to guarantee you get the same type of vaccine again."
The trial of mixed vaccines is funded by the vaccine taskforce and supported by the National Institute for Health Research. It is being run from nine different sites across England:
'Mix-and-match' Covid vaccines to be tested
Covid trial to examine mixing different vaccines
Guest Columnist Michael Quinlan: Mixing Healthier Foods With Vaccine Misinformation
I read Olin Rose-Bardawil's column in support for Robert F. Kennedy Jr. As Health and Human Services secretary ["RFK Jr. Could bring change to health woes," Gazette, Dec. 13]. And although RFK Jr. Has sounded the alarm about chronic diseases, there is little on his website offering solutions.
He has five stances listed on his site. First one is he wants Americans to eat healthier. In 2010, Michelle Obama instituted the "Let's Move" campaign, encouraging schools to change their lunch offerings for a healthier diet. Obesity in children has been a chronic problem and this program did successfully reduce obesity in younger children.
However, Republicans fought against this program and it ended in 2017, and it probably will not reach its goal of reducing child obesity by 5% in 2030. Maybe RFK Jr. Could use this as a model to convince his Republican friends to help people eat healthier.
When the Biden administration came into office they passed the Inflation Reduction Act, part of which lowered drug prices. The amount of money the U.S. Spends on health care is by far the highest in the world. And although many people have health insurance, drugs are not always covered. In the past people couldn't afford to buy medicines to get healthy, but under Biden's plan many drug prices will be capped. This will save people thousands of dollars yearly.
Again, Republicans have fought tooth and nail against this program and have vowed to repeal it under Trump. Hopefully RFK Jr. Can convince his Republican friends not to end this program.
But the biggest issue with RFK Jr. Is his anti-vaccine stance. Last week, it was released that one of RFK Jr.'s attorneys asked the FDA to revoke its approval of the polio vaccine. By 1994, polio had been eradicated in the Americas and although there is no cure for polio, vaccination has prevented it. In 2022, the U.S saw its first case of polio in three decades. Now it is reemerging in unvaccinated people in the U.S.
In 2019, amid an outbreak of measles in Samoa, RFK Jr. Visited the country and sent a letter to the country's prime minister saying the measles vaccine might have caused the outbreak. Partly because of his message, many people stopped getting vaccinated and over two years, 83 people died of measles in Samoa.
Vaccination has eliminated or greatly reduced death rates for many diseases. Why does RFK Jr. Want these diseases to reemerge? I think we should be very concerned if he becomes the health czar concerning his anti-vaccine stance.
When I read that Rose-Bardawil was going to write for the Gazette, I thought it was a great idea. I was hoping to hear what young people thought of issues that directly affected them. Obviously chronic diseases affects everyone, but I was more interested to hear what young people thought of other issues. I wonder if they would have ideas about political issues such as climate change, student debt, gun safety, health insurance, etc. Or nonpolitical issues, such as space exploration, money paid to superstar athletes, education reform or other concerns.
In the future, maybe someone could ask them. I am a fan of Rose-Bardawil and I'm hoping he's the one. I look forward to future columns.
Michael Quinlan lives in Southampton.
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