Mixing vaccines: does it offer better immunity against Covid-19 strains and what are the side effects?


Daniel Bardsley
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As research continues to develop new and amended coronavirus vaccines, scientists across the world are also looking at what happens when individuals are immunised with more than one type of shot.

Administering different vaccines may offer stronger immunity against Covid-19, something that is especially valuable as new variants emerge.

But before such an approach becomes routine, more findings are needed to understand the effectiveness of using more than one vaccine – and to ensure there are no serious side effects.

Trials indicate it's not only safe, but also highly effective. Evidence suggests that AZ/Pfizer mRNA is even more effective than AZ/AZ

“It seems an inherently good idea if you’re worried about the efficacy,” said Prof David Taylor, emeritus professor of pharmaceutical and public health policy at University College London.

“As the variants change, we’ll be introducing new antigens. It would be a sensible thing to do as and when a complementary vaccine becomes available.

"But we need data, we need trials.”

There are several reasons why it may be desirable to use different vaccines, including that it may lead to stronger immunity – something known as heterologous prime boosting.

When a person receives an adenovirus viral vector vaccine, such as the Oxford-AstraZeneca, there is a potential risk the immune system will react against the adenovirus. This is used as a vector to deliver coronavirus genetic material into human cells.

Dr Raghib Ali of New York University Abu Dhabi, says mixing vaccines shows good antibody response. Reem Mohammed / The National
Dr Raghib Ali of New York University Abu Dhabi, says mixing vaccines shows good antibody response. Reem Mohammed / The National

If this happens, when an individual is injected with the same vaccine again, some vaccine particles will be attacked by the recipient’s immune system, weakening the dose’s protective effect.

However, this will not affect mRNA vaccines – the technology behind those from Pfizer-BioNTech or Moderna.

Adenovirus viral vector vaccines use a weakened or inactivated virus to introduce coronavirus genetic material into cells, which then make coronavirus spike proteins, triggering an immune response.

The mRNA vaccines cause the body's cells to produce similar proteins, which again trigger an immune response.

Another reason to offer different doses is availability. If supplies of one vaccine dwindle, health authorities may welcome being able to give patients a different one for their second – or third – dose.

People who have had two doses of a vaccine with lower efficacy may want to have a booster of a different vaccine.

Also, concerns over rare blood clots caused by some viral vector vaccines may make it desirable to give individuals a different vaccine – such as an mRNA shot – for their subsequent shot.

This is why France announced in April that under 55s who had received the Oxford-AstraZeneca shot as their first dose would be given a Pfizer-BioNTech shot as their second, despite limited efficacy data being available. Other countries have introduced or are considering similar strategies.

Roy Cooper / The National
Roy Cooper / The National

Multiple trials involving giving people more than one Covid-19 vaccine are under way. Prof Zhou Xing, of the McMaster Immunology Research Centre at McMaster University, Canada, said results so far from studies in Germany and Spain are “very encouraging”.

“They indicate it’s not only safe, but also highly effective,” he said. “So far the evidence suggests that AZ/Pfizer mRNA is even more effective than AZ/AZ.”

A study published at the beginning of June looked at a cohort who received one dose of the Oxford-AstraZeneca vaccine followed eight weeks later by a Pfizer-BioNTech shot.

“We looked at neutralising antibody response: how the people that received the vaccinations responded with regards to antibodies in their blood or serum that actually neutralise virus,” said Ruediger Gross, of Ulm University Medical Centre in Germany, the first author of the study, which has yet to be peer reviewed.

Using blood sample extracts, they found that neutralisation of the Alpha variant was almost four times higher in people given the two different vaccines than it was in a group that had received two Pfizer-BioNTech doses.

"This doesn't necessarily mean that protection in the real world is fourfold higher, simply because protection for the double BioNTech vaccinated is already very high. But it indicates that it probably at least will be as good," he said.

Slight alterations in the coronavirus spike proteins generated by different vaccines may help to explain why using different shots is better than just one.

“It might help the immune system to simply see this protein from basically two different perspectives, to develop a better, broader immune response,” Mr Gross said.

Current studies involving more than one Covid-19 vaccine come with the caveat that results so far focus principally on laboratory tests.

“They show they produce good antibody response, which is important, but not the same as reducing hospitalisation and death,” said Dr Raghib Ali, director of the Public Health Research Centre at New York University Abu Dhabi.

He noted that at least one study has indicated a higher rate of side effects in people given different Covid-19 vaccines. Fever and headaches, for example, may be more common.

Ruediger Gross, a researcher at Ulm University in Germany, recently published a paper on the results of using more than one Covid-19 vaccine. Courtesy: Ulm University
Ruediger Gross, a researcher at Ulm University in Germany, recently published a paper on the results of using more than one Covid-19 vaccine. Courtesy: Ulm University

Giving several vaccines at once against different diseases is routine, with children receive as many as half a dozen in a single shot, but experience of giving an individual more than one vaccine against a single disease is limited, although there are precedents.

More than one vaccine has been employed against HIV, the virus that causes Aids, albeit with disappointing results.

Pharmaceutical company Johnson and Johnson created an effective two-dose vaccine against Ebola, the viral disease that has broken out several times in Africa in recent years.

The first dose uses an adenovirus viral vector, while the second employs a modified pox virus.

While more real-world efficacy data for Covid-19 vaccine combinations is awaited, Mr Gross said it may become more commonplace to give individuals more than one vaccine, particularly with third doses.

As coronavirus vaccines are largely being well tolerated, he suggests there are unlikely to be long-term side effects and he thinks it unlikely that third doses will be required to be of the same vaccine as the initial two shots.

Senior figures, such as Pfizer chief executive Albert Bourla, have suggested a third dose might be needed six to 12 months after the second, followed by annual vaccination.

However, some people who have received two doses of Covid-19 vaccines that appear to have lower efficacy may be keen to have a third shot of a different vaccine sooner than this.

In Abu Dhabi booster third vaccine doses are being made available six months after second shots.

Mr Gross said in principle there is no reason why an interval of several months is needed between second and third doses.

“I don’t think it necessarily needs to be half a year if your response to the first two vaccines was not great,” he said.

Indeed, in a study that announced findings this month, immunocompromised individuals who had reacted poorly to two doses of a vaccine were given a third shot as little as 24 days later.

In this research, one third of patients who had failed to develop antibodies after two doses did produce them after their third.

With multiple combinations of different vaccines being trialled, clinicians will be keeping a close eye on results to inform future Covid-19 vaccination strategies.

And the experiences gained during the pandemic in using more than one vaccine may offer wider benefits into the future, suggested Prof Xing.

“Since both adenoviral vector vaccines and mRNA-based vaccines are very new to us, going forward our experience in mixing them in the fight against Covid-19 certainly will lend to developing vaccines against other infectious diseases,” he said.

Production of Hayat-Vax – in pictures

Indoor cricket World Cup:
Insportz, Dubai, September 16-23

UAE fixtures:
Men

Saturday, September 16 – 1.45pm, v New Zealand
Sunday, September 17 – 10.30am, v Australia; 3.45pm, v South Africa
Monday, September 18 – 2pm, v England; 7.15pm, v India
Tuesday, September 19 – 12.15pm, v Singapore; 5.30pm, v Sri Lanka
Thursday, September 21 – 2pm v Malaysia
Friday, September 22 – 3.30pm, semi-final
Saturday, September 23 – 3pm, grand final

Women
Saturday, September 16 – 5.15pm, v Australia
Sunday, September 17 – 2pm, v South Africa; 7.15pm, v New Zealand
Monday, September 18 – 5.30pm, v England
Tuesday, September 19 – 10.30am, v New Zealand; 3.45pm, v South Africa
Thursday, September 21 – 12.15pm, v Australia
Friday, September 22 – 1.30pm, semi-final
Saturday, September 23 – 1pm, grand final

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Fifa%20World%20Cup%20Qatar%202022%20
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UAE WARRIORS RESULTS

Featherweight

Azouz Anwar (EGY) beat Marcelo Pontes (BRA)

TKO round 2

Catchweight 90kg

Moustafa Rashid Nada (KSA) beat Imad Al Howayeck (LEB)

Split points decision

Welterweight

Gimbat Ismailov (RUS) beat Mohammed Al Khatib (JOR)

TKO round 1

Flyweight (women)

Lucie Bertaud (FRA) beat Kelig Pinson (BEL)

Unanimous points decision

Lightweight

Alexandru Chitoran (ROU) beat Regelo Enumerables Jr (PHI)

TKO round 1

Catchweight 100kg

Marc Vleiger (NED) beat Mohamed Ali (EGY)

Rear neck choke round 1

Featherweight

James Bishop (NZ) beat Mark Valerio (PHI)

TKO round 2

Welterweight

Abdelghani Saber (EGY) beat Gerson Carvalho (BRA)

TKO round 1

Middleweight

Bakhtiyar Abbasov (AZE) beat Igor Litoshik (BLR)

Unanimous points decision

Bantamweight

Fabio Mello (BRA) beat Mark Alcoba (PHI)

Unanimous points decision

Welterweight

Ahmed Labban (LEB) v Magomedsultan Magomedsultanov (RUS)

TKO round 1

Bantamweight

Trent Girdham (AUS) beat Jayson Margallo (PHI)

TKO round 3

Lightweight

Usman Nurmagomedov (RUS) beat Roman Golovinov (UKR)

TKO round 1

Middleweight

Tarek Suleiman (SYR) beat Steve Kennedy (AUS)

Submission round 2

Lightweight

Dan Moret (USA) v Anton Kuivanen (FIN)

TKO round 2

RACE CARD

6.30pm Al Maktoum Challenge Round-1 Group 1 (PA) Dh119,373 (Dirt) 1,600m

7.05pm Handicap (TB) Dh102,500 (D) 1,200m

7.40pm Handicap (TB) Dh105,000 (Turf) 1,800m

8.15pm UAE 1000 Guineas Trial (TB) Dh183,650 (D) 1,400m

9.50pm Handicap (TB) Dh105,000 (D) 1,600m

9.25pm Handicap (TB) Dh95,000 (T) 1,000m

The Library: A Catalogue of Wonders
Stuart Kells, Counterpoint Press

Ziina users can donate to relief efforts in Beirut

Ziina users will be able to use the app to help relief efforts in Beirut, which has been left reeling after an August blast caused an estimated $15 billion in damage and left thousands homeless. Ziina has partnered with the United Nations High Commissioner for Refugees to raise money for the Lebanese capital, co-founder Faisal Toukan says. “As of October 1, the UNHCR has the first certified badge on Ziina and is automatically part of user's top friends' list during this campaign. Users can now donate any amount to the Beirut relief with two clicks. The money raised will go towards rebuilding houses for the families that were impacted by the explosion.”

What is dialysis?

Dialysis is a way of cleaning your blood when your kidneys fail and can no longer do the job.

It gets rid of your body's wastes, extra salt and water, and helps to control your blood pressure. The main cause of kidney failure is diabetes and hypertension.

There are two kinds of dialysis — haemodialysis and peritoneal.

In haemodialysis, blood is pumped out of your body to an artificial kidney machine that filter your blood and returns it to your body by tubes.

In peritoneal dialysis, the inside lining of your own belly acts as a natural filter. Wastes are taken out by means of a cleansing fluid which is washed in and out of your belly in cycles.

It isn’t an option for everyone but if eligible, can be done at home by the patient or caregiver. This, as opposed to home haemodialysis, is covered by insurance in the UAE.

COMPANY PROFILE
Name: Kumulus Water
 
Started: 2021
 
Founders: Iheb Triki and Mohamed Ali Abid
 
Based: Tunisia 
 
Sector: Water technology 
 
Number of staff: 22 
 
Investment raised: $4 million 
What is the FNC?

The Federal National Council is one of five federal authorities established by the UAE constitution. It held its first session on December 2, 1972, a year to the day after Federation.
It has 40 members, eight of whom are women. The members represent the UAE population through each of the emirates. Abu Dhabi and Dubai have eight members each, Sharjah and Ras al Khaimah six, and Ajman, Fujairah and Umm Al Quwain have four.
They bring Emirati issues to the council for debate and put those concerns to ministers summoned for questioning. 
The FNC’s main functions include passing, amending or rejecting federal draft laws, discussing international treaties and agreements, and offering recommendations on general subjects raised during sessions.
Federal draft laws must first pass through the FNC for recommendations when members can amend the laws to suit the needs of citizens. The draft laws are then forwarded to the Cabinet for consideration and approval. 
Since 2006, half of the members have been elected by UAE citizens to serve four-year terms and the other half are appointed by the Ruler’s Courts of the seven emirates.
In the 2015 elections, 78 of the 252 candidates were women. Women also represented 48 per cent of all voters and 67 per cent of the voters were under the age of 40.
 

The Two Popes

Director: Fernando Meirelles

Stars: Anthony Hopkins, Jonathan Pryce 

Four out of five stars

GAC GS8 Specs

Engine: 2.0-litre 4cyl turbo

Power: 248hp at 5,200rpm

Torque: 400Nm at 1,750-4,000rpm

Transmission: 8-speed auto

Fuel consumption: 9.1L/100km

On sale: Now

Price: From Dh149,900

BMW M5 specs

Engine: 4.4-litre twin-turbo V-8 petrol enging with additional electric motor

Power: 727hp

Torque: 1,000Nm

Transmission: 8-speed auto

Fuel consumption: 10.6L/100km

On sale: Now

Price: From Dh650,000

The biog

Full name: Aisha Abdulqader Saeed

Age: 34

Emirate: Dubai

Favourite quote: "No one has ever become poor by giving"

UNSC Elections 2022-23

Seats open:

  • Two for Africa Group
  • One for Asia-Pacific Group (traditionally Arab state or Tunisia)
  • One for Latin America and Caribbean Group
  • One for Eastern Europe Group

Countries so far running: 

  • UAE
  • Albania 
  • Brazil 
Cricket World Cup League 2

UAE results
Lost to Oman by eight runs
Beat Namibia by three wickets
Lost to Oman by 12 runs
Beat Namibia by 43 runs

UAE fixtures
Free admission. All fixtures broadcast live on icc.tv

Tuesday March 15, v PNG at Sharjah Cricket Stadium
Friday March 18, v Nepal at Dubai International Stadium
Saturday March 19, v PNG at Dubai International Stadium
Monday March 21, v Nepal at Dubai International Stadium

Company profile

Name: The Concept

Founders: Yadhushan Mahendran, Maria Sobh and Muhammad Rijal

Based: Abu Dhabi

Founded: 2017

Number of employees: 7

Sector: Aviation and space industry

Funding: $250,000

Future plans: Looking to raise $1 million investment to boost expansion and develop new products

Lewis Hamilton in 2018

Australia 2nd; Bahrain 3rd; China 4th; Azerbaijan 1st; Spain 1st; Monaco 3rd; Canada 5th; France 1st; Austria DNF; Britain 2nd; Germany 1st; Hungary 1st; Belgium 2nd; Italy 1st; Singapore 1st; Russia 1st; Japan 1st; United States 3rd; Mexico 4th

What went into the film

25 visual effects (VFX) studios

2,150 VFX shots in a film with 2,500 shots

1,000 VFX artists

3,000 technicians

10 Concept artists, 25 3D designers

New sound technology, named 4D SRL

 

UAE currency: the story behind the money in your pockets
Company%20profile
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Brief scoreline:

Al Wahda 2

Al Menhali 27', Tagliabue 79'

Al Nassr 3

Hamdallah 41', Giuliano 45 1', 62'