London Daily

Focus on the big picture.

All You Need To Know About Switching, Spacing Covid Vaccine Doses

All You Need To Know About Switching, Spacing Covid Vaccine Doses

All COVID-19 vaccines approved, so far, are designed to teach the immune system to recognise and defend against the virus with a first dose, and then provide a second booster dose to reinforce that lesson.

Britain and other nations are considering ways to stretch scarce supplies of COVID-19 vaccines, including by delaying second doses, reducing dose sizes and switching vaccine types between the first and second shots.

The proposals have generated fierce debate among scientists. The following is the rationale behind, and criticism of, these alternative strategies:

Why delay the second dose?


In clinical trials, companies tested specific doses of their vaccines at precise time intervals to generate evidence showing how well they work. All COVID-19 vaccines approved, so far, are designed to teach the immune system to recognise and defend against the virus with a first dose, and then provide a second booster dose to reinforce that lesson.

Faced with surging pandemic and new, more transmissible coronavirus variants, some countries are hoping to broaden immunisation by giving some protection to as many people as possible with a first dose, and delaying second doses.

Maximising the number of people who have partial immunity "should reduce the number of severe COVID-19 cases and thus alleviate the burden on hospitals", said Michael Head, a global health expert at Britain's University of Southampton.

What about switching between COVID-19 vaccines?


Mixing or switching between COVID-19 vaccines is largely driven by the same aim - vaccinating as many people as possible as the pandemic still rages.

Giving a priming dose of one vaccine and a booster dose of another offers flexibility to offer whichever shots are available, rather than holding shots back so individuals always get both doses of the same vaccine.

Have these strategies been tested in rigorous trials?


No.

None of the late-stage COVID-19 vaccine trials compared these dose-sparing strategies or the effects of mixing vaccine types, said Stephen Evans, a professor of pharmacoepidemiology at the London School of Hygiene & Tropical Medicine (LSHTM).

Officials have cited limited evidence from trials that the Pfizer/BioNTech, the Oxford University/AstraZeneca and the Moderna vaccines all confer some protection against COVID-19 after the first dose.

Britain's MHRA health regulator on December 30 said it had found an 80 per cent effectiveness rate for the Oxford/AstraZeneca vaccine when two full doses are administered three months apart, higher than the average that the developers themselves had found.

A day later, the UK government's vaccine advisory committee said the Pfizer/BioNTech vaccine conferred 89 per cent protection from two weeks after the first dose, and that for the Oxford/AstraZeneca vaccine "the evidence shows that the initial dose ... offers as much as 70 per cent protection against the effects of the virus". It did not give detailed data.

Moderna reported its vaccine was 80 per cent protective after one dose, with efficacy peaking two weeks after the first shot.

There is no long-term evidence that any of these vaccines will offer lasting immunity based on just one dose, or how effective they will be if the second dose is delayed.

BioNTech and Pfizer warned on Monday they had no evidence their vaccine would continue to be protective if the second dose was given more than 21 days after the first.

Ideally, "it is safest and most cautious" to use vaccines in conditions exactly matching those of their trials, Evans said, but added: "In the real world, this is never so."

Dr. Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases, told CNN on Friday the United States was unlikely to delay giving second doses.

"We're going to keep doing what we're doing," he said.

Likewise, scientists have raised concerns over the idea of mixing two different types of vaccines. Some experts speculate that, because all of the vaccines target the same outer "spike" protein of the virus, they could work together to train the body to fight off the virus.

There is no evidence this approach will work.

"There is literally zero data. It has not been tested, or if it has been tested, the data have not been made available," said John Moore, a professor of microbiology and immunology at Weill Cornell Medical College in New York.

What about reducing the amount of vaccine in each dose?


In the United States, some health officials are considering offering half doses of Moderna's vaccine to individuals aged 18 to 55. There is some clinical trial data backing this strategy.

Moncef Slaoui, chief adviser to the U.S. Operation Warp Speed vaccine programme , told CBS on Sunday that evidence from a Moderna trial showed the half dose induced an "identical immune response" to the higher 100 microgram dose in adults aged 55 and under. He said the US government was discussing the issue with Moderna and regulators.

Slaoui said he believed injecting half of the volume of vaccine was "a more responsible approach that would be based on facts and data".

Several US scientists agreed, but noted the data was not publicly available. "It's very fuzzy. I want to see that data," said Eric Topol, a genomics expert and director of the Scripps Research Translational Institute in La Jolla, California.

Moderna Chief Executive Stephane Bancel said on Tuesday he does not believe existing data from trials on the efficacy of a half-dose version would be sufficient to convince regulators, doctors or governments to approve such a move. "That data has not been published yet. It will be soon," Bancel said at a Goldman Sachs event.

"I don't see a world where that data is enough to convince the medical community, the (Vaccines and Related Biological Products Advisory Committee) and of course the agency (U.S. Food and Drug Administration), to move to 50 micrograms at this stage," he said.

So are these strategies safe? and will they work?


It is not clear.

While there is no scientific evidence on the impact of delaying COVID-19 vaccine doses, some experts believe it could be safe to wait, and the potential payoff in protecting a larger swath of the population may be worth it.

Others are not so sure.

"There's just no data," said Ian Jones, a professor of virology at Britain's Reading University.

The British Society of Immunology said in a statement on Monday that delaying a second dose by eight weeks "would be unlikely to have a negative effect on the overall immune response". It added that it would not expect any extra safety risks from the delay beyond the potential increased risk of contracting the disease during the gap between doses.

Some scientists also said that while there was no evidence to support the strategy of mixing vaccine doses from different manufacturers - a method known as heterologous prime-boost - evidence from other vaccines provided some reassurance.

"Based on previous studies which combine different vaccine types, a combination of the AstraZeneca and Pfizer vaccines is likely to be safe," said Helen Fletcher, a professor of immunology at LSHTM.

Topol, however, called the mix-and-match strategy "a big mistake" with "unpredictable" results - including the potential for adverse reactions or a significant dropoff in efficacy. "It makes no sense whatsoever," he said.

Some worry about safety issues, particularly with delaying the second dose for several weeks. The gap could allow time for the virus to evolve and develop resistance to the vaccine.

Weak antibody protection could also increase the risk of an abnormal immune response - such as antibody-dependent enhancement - when people encounter the real virus, Topol said.

How practical is it to prolong dosing schedules?


Extending the interval poses adherence risks, raising the chance people may forget or fail to return for a second dose.

It also increases the length of time during which they are less than optimally protected. And it could make it harder for health authorities to keep track of who has had which vaccine, when, and how often.

Given these risks, immunology and public health experts say clear communication is imperative to ensure people understand that although dosing schedules may be subject to change, two COVID-19 vaccine doses are needed to give the best protection.

Comments

Oh ya 3 year ago
Just think about this. It has been reported that about half of the frontline medical people who are dealing with this everyday have refused to take the vaccine. Ask your self what do they know that the lying MSM and vaccine pushers are not telling you. And if you still decide to be a lab rat at least do not force your kids to be one

Newsletter

Related Articles

London Daily
0:00
0:00
Close
Unelected PM of the UK holds an emergency meeting because a candidate got voted in… which he says is a threat to democracy…
You Are So Beautiful
Rob Schneider explains California reparations legislation.
Postmodern Jukebox European Tour Version
Who knew badminton could get so intense?
An old French tune (by Georges Brassens) Pomplamoose ft. John Schroeder
Farmers break through police barriers in Brussels.
Sattahip Motor Show 20
London's Iconic British Telecom Tower Sold To Become Hotel
SONATE AU CLAIR DE LUNE - Moonlight sonata
Ukraine Arrests Father-Son Duo In Lockbit Cybercrime Bust
A kiss to build a dream on
US Offers $15 Million For Info On Leaders Of Cybercrime Group Lockbit
Wonderful Tonight - Eric Clapton (Boyce Avenue acoustic cover)
Russia Claims UK Cultural Agency Spied for Ukraine
Mean Blues
Apple warns against drying iPhones with rice
La Chansonnette
Alexei Navalny: UK sanctions Russian prison chiefs after activist's death
Pattaya Addicts
German economy is in 'troubled waters' - ministry
Franz Liszt - Liebestraum - Love Dream
In a recent High Court hearing, the U.S. argued that Julian Assange endangered lives by releasing classified information.
Dream a little dream of me
New video
Unchained Melody sung like you've NEVER heard!
Tucker Carlson says Boris Johnson wants "a million dollars, in Bitcoin or cash, from Tucker Carlson to talk about Ukraine.
Dave Brubeck - Take Five
Russia is rebuilding capacity to destabilize European countries, new UK report warns
Édith Piaf - Non, Je Ne Regrette Rien (Sofie)
EU Commission wants anti-drone defenses at Brussels HQ
Rondo Alla Turca
Von der Leyen’s 2nd-term pitch: More military might, less climate talk
Kiss of fire
Global Law Enforcement Dismantles Lockbit Ransomware Operation
Tom Jones - I´ll Never Fall In Love Again 1967, 1989, 2001
Prince William Urges End to Gaza Conflict
Israel Cachao López - Guajira Clásica
UK court to hear Assange's final appeal against extradition to the US, where he faces charges related to his journalistic work—the publication of a classified video in 2010 that exposed US war crimes against humanity.
Edward Maya - Stereo Love (feat. Vika Jigulina) (Extended Mix)
About 50-60% kids either chose to be YouTuber or influencer
Strauss - Radetzky March - Karajan
A viral video of Nationals MP Barnaby Joyce lying on a Canberra footpath is celebrated by his media mates.
La vie en rose
European Countries React to Navalny's Death by Summoning Russian Diplomats
The Temptations - My Girl (Smokey Robinson Tribute) 2006 Kennedy Cent
Israel has gone ‘beyond self-defence’ in Gaza, says Labour’s Streeting
Orlando Cachaito Lopez Redencion
English farmers to be offered ‘largest ever’ grant scheme amid food security concerns
Edith Piaf - NON, JE NE REGRETTE RIEN
Cameron government knew Post Office ditched Horizon IT investigation
RADETZKY MARCH-2008-Wien, New Year Concert
EU Calls for Immediate Ceasefire in Gaza Conflict
Only you (And you alone)
EU Vows To Hold Putin "Accountable" After Meeting Alexei Navalny's Wife
Strangers In The Night
EU Launches Probe Into TikTok Over Child Protection Under Digital Content Law
Charles Aznavour - La Boheme
The EU Initiates Naval Mission to Defend Red Sea Trade Routes
Summer time
EU and UK Announce Joint Effort on Migration
Sting and Stevie Wonder - Fragile (from Sting's 60th birthday concert)
Brazil's Lula Likens Gaza Operation to Holocaust, Israel Says "Red Line" Crossed
Aux Champs Elysees
Ministers Confirm Proposal to Prohibit Mobile Phone Usage in English Schools
Stand By Me - Ben E. King (Boyce Avenue acoustic cover)
Microsoft-backed OpenAI valued at $80bn after company completes deal
La Mer (Beyond the Sea) – Avalon Jazz Band
‘Alexei would want to tell Russia not to give up fighting’
She
Rwandan Footballer's Dismissal Sparks Concerns Over UK Asylum Plan
Nathalie Song by Enzo Petrachi Stjepan Hauser Cello
Whisky Challenges China's Baijiu Market During New Year Celebrations
Shape of My Heart - Sting (Boyce Avenue acoustic cover)
Avdiivka - Symbol Of Ukrainian Resistance Now In Control Of Russian Troops
Radiohead - Creep
Putin Critic Alexei Navalny's "Killers" Refusing To Hand Over Body, Say Allies
Quizás,Quizás,Quizás - Andrea Bocelli - Jennifer Lopez
"Historic Step": Zelensky Signs Security Pact With Germany
Perhaps, Perhaps, Perhaps - Multi-Couples
"Historic Step": Zelensky Signs Security Pact With Germany
Pentatonix Havana
20 Tech Giants Sign Effort To Fight AI Election Interference Across Globe
Paula Cole - Autumn Leaves
Joe Biden Accuses Putin of Causing Navalny's Death
Oscar Benton Bensonhurst Blues
Russian opposition leader Alexey Navalny has died at the Arctic prison colony
OH NANANA vs ABUSADAMENTE
Tucker Carlson grocery shopping in Russia. This is so interesting.
Nina Simone - ”I Put A Spell On You”. Vezi aici cum cântă Jeremy Ragsd
Julian Assange's Wife Warns of His Death if Extradited to US
NIGHTWISH - The Phantom Of The Opera
‘A lot higher than we expected’: Russian arms production worries Europe’s war planners
Motorshow 2016 Tanjay Negros Oriental
Greece Legalizes Same-Sex Marriage and Adoption Rights
Monica Bellucci - Ti Amo
Hungarian Foreign Minister: Europeans will lose Europe, the Union's policy must change drastically
Michael Jackson - Billie Jean Milena The Voice France 2018
In Britain Homeowners are receiving CPO’s (Compulsory Purchase Orders) so their homes can be redistributed to migrants
Michael Buble (Help Me Make It Through The Night) feat Loren Allred
Memories Canon In D - Maroon 5 (Boyce Avenue piano acoustic cover)
Matteo Simoni - Marina
Maroon 5 - One More Night
Maroon 5 - Memories
Mark Knopfler - Brothers In Arms (Berlin 2007 Live)
Mark Knopfler & Emmylou Harris - Romeo And Juliet (Real Live Roadrunni
Marina, Marina - The LUCKY DUCKIES intimist live concert at Guimarães
Major Lazer & DJ Snake – Lean On Mauranne The Voice France 2016
Love Theme from Romeo and Juliet - Joslin - Henri Mancini, Nino Rota
LoLa & Hauser - Love Story
Linkin Park Jay-Z - Numb Encore (Live 8 2005)
Hallelujah Mennel Ibtissem, The Voice France Leonard Cohen
Leonard Cohen - Dance Me to the End of Love
Leonard Cohen & Natasha Rostova - Dance me to the end of love
La casa de papel - Bella Ciao
La Camisa Negra
L'italiano (Toto Cutugno) - The Gypsy Queens
Juanes - La Camisa Negra
Jonathan and Charlotte - Britain's Got Talent 2012 Live Semi Final - U
John Powell - Assassin's Tango
Joe Cocker - You Can Leave Your Hat On (LIVE in Dortmund)
Joe Cocker - Unchain My Heart 2002 Live
Joe Cocker - A Whiter Shade Of Pale
Jay Z & Alicia Keys - Empire State of Mind LIVE
Jason Mraz - Im Yours (live)
Jarrod Radnich - Bohemian Rhapsody - Virtuosic Piano Solo
James Blunt - You're Beautiful
James Blunt - You're Beautiful & Bonfire Heart (Live at The Nobel Peac)
If You Go Away - Helen Merrill & Stan Getz (Tribute to Virna Lisi)
I'LL BE MISSING YOU
I Say a Little Prayer
Hotel California ( Eagles ) 1994 Live
Historia de un amor - Luz Casal. Vezi interpretarea Biancăi Sumanariu
Here Comes The Sun - The Beatles (Boyce Avenue acoustic cover) on Spot
Heart - Stairway to Heaven Led Zeppelin - Kennedy Center Honors
HAVANA by Camila Cabello Zumba Pre Cooldown TML Crew Kramer Pastra
HAUSER and Señorita - I Will Always Love You
HAUSER - Waka Waka
HAUSER - Sway
HAUSER - Lambada
HAUSER - Historia de un Amor
HAUSER - Despacito
Great Pretender
Georgia May Foote & Giovanni Pernice Samba to 'Volare' - Strictly Come
Gary Moore - Still Got The Blues
GIPSY KINGS VOLARE Penelope Cruz
Fugees - Killing Me Softly With His Song
French Latino - Historia de un Amor
For A Few Dollars More The Danish National Symphony Orchestra (Live)
Flashdance • What a Feeling • Irene Cara
Filip Rudan - “Someone You Loved” Audicija 4 The Voice Hrvatska Sez
Eric Clapton - Wonderful Tonight
Enya - Only Time
Enrique Iglesias - Bailando (English Version) ft. Sean Paul
Enrique Iglesias - Bailamos
Elena Yerevan Historia de un amor
Ed Sheeran - Shape of You (Official Music Video)
Ed Sheeran - Perfect Symphony [with Andrea Bocelli]
Ed Sheeran - Perfect (Official Music Video)
Easy On Me - Adele (Boyce Avenue 90’s style piano acoustic cover) on S
ERA - Ameno
ELENA YEREVAN- Cancion Del Mariachi-IN STUDIO-2017 DPR
Dust In The Wind - Kansas (Boyce Avenue acoustic cover)
Don't Let Me Be Misunderstood
Despacito x Shape Of You - Pentatonix
Deep Purple - Child In Time - Live (1970)
David Foster When A Man Loves A WomanIt's A Mans World (SealMichael Bo
Dance me to the end of Love ( Pi-Air Design )
Coolio - Gangsta's Paradise (feat. L.V.) [Official Music Video]
Conquest Of Paradise (Vangelis), played on Böhm Emporio organ
Cielito Lindo
Chico & The Gypsies - Bamboleo
Canción Del Mariachi - Antonio Banderas, Los Lobos • Desperado
Camila Cabello - Havana (Audio) ft. Young Thug
Camila Cabello - Havana ( cover by J.Fla )
California Dreamin' - The Mamas & The Papas José Feliciano (Boyce Ave
Buster Benton - Money Is The Name of The Game
Hallelujah Pentatonix
Bobby McFerrin - Don't Worry Be Happy (Official Music Video)
Bob Dylan - Knockin' On Heaven's Door Emilia The Voice Kids France
Besame Mucho - Cesaria Evora
Ben E. King - Stand by Me Sax Cover Alexandra Ilieva Thomann
Bella Ciao
Bella Ciao - INSTRUMENTAL
Beautiful in White x Canon in D (Piano Cover by Riyandi Kusuma)
Bad Romance - Vintage 1920's Gatsby Style Lady Gaga Cover ft. Ariana Savalas & Sarah Reich(1)
BELLA CIAO 2020 - KARAOKE ITALIANO
BAMBOLEO - Gipsy Kings • Antonio Banderas, Katya Virshilas
BAILANDO (original)
Awesome Ukrainian yodeler - SOFIA SHKIDCHENKO (with English subtitles)
Avicii - The Nights
Atom - The Great Gig in the Sky
Aretha Franklin - (You Make Me Feel Like) A Natural Woman (Official Ly
Antonio Banderas - Cancion del Mariachi (Desperado)
André Rieu - Zorba's Dance (Sirtaki)
André Rieu - Can't Help Falling In Love
André Rieu & Mirusia - Ave Maria
Andrew Reyes Elton John - Don't Let The Sun Go Down The Voice 2020 (
Andreas Kümmert Whiter Shade Of Pale The Voice of Germany 2013 Showd
And I Love You So
All About That Bass - Postmodern Jukebox European Tour Version
Alan Walker - Faded (Piano Cover)
Ain't No Sunshine -- Bill Withers (cover by Canen 12 y.o.)
African music
Adriana Vidović - “Creep” Audicija 4 The Voice Hrvatska Sezona 3
Adriana Vidović - “Believer” Nokaut 3 The Voice Hrvatska Sezona 3
A Fistful of Dollars - The Danish National Symphony Orchestra and Tuva
4 Beautiful Soundtracks Relaxing Piano [10min]
2CELLOS - Whole Lotta Love vs. Beethoven 5th Symphony [OFFICIAL VIDEO]
2CELLOS - Smooth Criminal (Live at Suntory Hall, Tokyo)
2CELLOS - Smells Like Teen Spirit [Live at Sydney Opera House]
2CELLOS - Despacito [OFFICIAL VIDEO]
13 Year Old Girl Playing Il Silenzio (The Silence) - André Rieu
094.All About That Bass
00 - SADNESS PART 1
(Ghost) Riders In the Sky (American Outlaws Live at Nassau Coliseum, 1
(Everything I Do) I Do It For You - Bryan Adams (Boyce Avenue ft. Conn
What a wonderful world
Moon river
×