The study is small but adds to data finding benefits of mix-and-match boosting.

switch to moderna booster after pfizer shots better against omicron in 60+

/ The Comirnaty (Pfizer/BioNTech) and Moderna COVID-19 vaccines.Getty | Marcos del Mazo

People ages 60 and older who were initially vaccinated with two Pfizer-BioNTech COVID-19 vaccine doses were better protected from the omicron coronavirus variant after being boosted with a Moderna vaccine rather than another dose of the Pfizer-BioNTech vaccine.

Those results are according to interim data from a small but randomized controlled clinical trial in Singapore and published this week in the journal Clinical Infectious Diseases.

The study—involving 98 healthy adults—can’t determine if the Moderna booster is simply superior to a Pfizer-BioNTech booster for older adults or if a mix-and-match booster strategy is inherently better. It also focused solely on antibody levels, which may or may not translate to significant differences in infection rates and other clinical differences. It also only followed people for 28 days after a booster, so it’s unclear if the Moderna booster’s edge will hold up over time.

Still, the authors of the study, led by Barnaby Young of Singapore’s National Centre for Infectious Diseases, report that the beneficial effect seen by swapping from Pfizer-BioNTech to Moderna was significant enough that they don’t expect it to vanish with more participants. It also follows other studies that have suggested that mix-and-match boosting—aka heterologous boosting—can generate slightly different antibodies and reduce the incidence of SARS-CoV-2 infections in people 60 and older.

For the new study, Young and colleagues looked at antibody levels in adults of all ages who had received two Pfizer-BioNTech COVID-19 vaccine doses between six and nine months before receiving a booster dose. The researchers excluded people from the trial if they had compromised immune systems or had evidence of prior SARS-CoV-2 infections (the presence of anti-N antibodies).

Of the 98 participants, 50 went on to get another Pfizer-BioNTech vaccine dose for their booster (homologous booster), while the remaining 48 received a Moderna booster (heterologous booster). The authors looked at their resulting antibody responses on the day of their booster, seven days later, and 28 days later. Specifically, they compared total levels of antibodies that targeted a key part of the SARS-CoV-2 spike protein, called the receptor-binding domain. They also looked at levels of neutralizing antibodies against a range of specific SARS-CoV-2 variants, from the ancestral strain to alpha, beta, delta, and omicron.

Slightly bigger boost

Overall, the heterologous-boosted group had slightly higher total antibody levels than the homologous group—about 40 percent higher on day seven and 30 percent higher on day 28, though the confidence intervals overlapped. But, when the authors broke out the groups by age, they found that the benefit was entirely from differences in the 60-and-up group. Antibody levels were equivalent among younger participants, regardless of booster type.

Among those 60 and older, there were 24 homologous-boosted participants and 23 heterologous-boosted participants. At seven days after the booster, the heterologous-boosted participants had two-fold higher antibody levels than the homologous group and 60 percent higher levels at 28 days.

Older heterologous-boosted participants also had higher levels of neutralizing antibodies against all of the SARS-CoV-2 variants tested—with the largest difference seen against omicron, which is notorious for thwarting vaccine-derived immune responses. At seven days, the level of neutralizing antibody inhibition was 89 percent in the heterologous-boosted group compared with 64 percent in the homologous-boosted group. At 28 days, the spread was 84 percent in the heterologous-boosted group to 73 percent in the homologous-boosted group.

Overall, Young and co-authors concluded: “For the vulnerable older age group in particular, a heterologous booster COVID-19 vaccine regimen induces a higher anti-spike antibody titer and a stronger neutralizing antibody response against the highly infectious Omicron variant (~20 percent higher neutralization) than a homologous booster regimen.”

The trial is still ongoing, so the authors will continue to add participants and data. They intend to reassess antibody responses in all participants at six months and 12 months after the booster. They will add people to the study who initially received Moderna vaccines to see if switching to the Pfizer-BioNTech vaccine for the booster offers a similar benefit.

NEWS RELATED

CDC presumes community spread of monkeypox; 9 cases now in 7 states

Some US cases had recent international travel to areas with cases, others did not.

View more: CDC presumes community spread of monkeypox; 9 cases now in 7 states

Can we cut the US’s carbon emissions in half this decade?

There are multiple routes to drop carbon emissions by 50% by 2030.

View more: Can we cut the US’s carbon emissions in half this decade?

Wild animals are evolving faster than anybody thought

How fast is evolution? In adaptive evolution, natural selection causes genetic changes in traits that favour the survival and reproduction of individual organisms. Although Charles Darwin thought the process occurred over geological timescales, we have seen examples of dramatic adaptive evolution over only a handful of generations. The peppered moth ...

View more: Wild animals are evolving faster than anybody thought

Super Cyclones Will Be Even More Devastating in the Future

A new study has revealed super cyclones, the most intense form of tropical storms, are likely to have a much more devastating impact on people in South Asia in future years. The international study, conducted by the University of Bristol, examined the 2020 Super Cyclone Amphan – the most ...

View more: Super Cyclones Will Be Even More Devastating in the Future

Harnessing the Immune System to Treat Traumatic Brain Injury

Summary: A new mouse study identifies a targeted delivery method system that boosts the number of specialized anti-inflammatory immune cells within the brain to areas restricted by brain inflammation and damage. The system helped to protect against apoptosis associated with brain injury, stroke, and multiple sclerosis. Source: Babraham Institute A ...

View more: Harnessing the Immune System to Treat Traumatic Brain Injury

Where rivers jump course: First global compilation of river avulsions

Credit: Unsplash/CC0 Public Domain Humans have always had a complex relationship with rivers, which both fostered and threatened civilizations throughout history. Just recall Osiris, the ancient Egyptian god of death and rebirth, who was inextricably linked with the annual flooding of the Nile. Large floods will sometimes force a ...

View more: Where rivers jump course: First global compilation of river avulsions

Researcher describes how extraterrestrial civilizations could colonize the galaxy even if they don't have starships

Credit: CC0 Public Domain Astronomers have searched for extraterrestrial civilizations in planetary systems for sixty years, to no avail. In the paper published by International Journal of Astrobiology, Cambridge University Press, and titled “Migrating extraterrestrial civilizations and interstellar colonization: Implications for SETI and SETA,” Irina K. Romanovskaya proposes that ...

View more: Researcher describes how extraterrestrial civilizations could colonize the galaxy even if they don't have starships

Research says watching TV every day might be slowly killing you

Watching more than one hour of TV each day may increase your risk of heart disease, a new study says. Researchers from the Medical Research Council (MRC) Epidemioligy Unit and the Universities of Cambridge and Hong Kong published new findings in the journal BMC Medicine. In fact, their findings ...

View more: Research says watching TV every day might be slowly killing you

Exposing Liars by Distraction – Science Reveals a New Method of Lie Detection

Seattle democracy vouchers increase donations, number of candidates in city elections

New non-radioactive, neutral reagent reveals viruses in clear detail

Bags or bins? When it comes to recycling, the answer is complicated

Gun violence: Experts discuss causes, trends, solutions

Three chaperones coordinate the breakup of amyloid fibrils in yeast

Could Ultrasound Help the Blind See?

What's the best way to remove mould? We asked an expert

Hot-Blooded or Cold-Blooded? Chemical Clues Solve One of the Oldest Mysteries in Paleontology

How to tie-dye cotton with acorns and rust

NASA looks to solar sails as a way to power future missions

Models predict that planned phosphorus reductions will make Lake Erie more toxic

OTHER NEWS