Accelerating Development for Some NextGen Covid Vaxes (Update No 39)

Image credit

Cartoon by Hilda Bastian, CC BY-NC-ND 4.0

Several next generation Covid vaccines are now advancing into mid- or late-stage trials. So this month, I have started a new section—a watchlist of featured vaccines that are both at more advanced stages of development, and reporting ongoing recent progress. I highlight 3 vaccines in particular—from Japan, South Korea, and the US—with a further 6 included in the watchlist. I hope this focus on advancing vaccines will make the progress in next generation vaccines clearer. The post begins there.

There is also an additional report of clinical trial results, plus 10 new reports of preclinical research. I have these broken down into the usual 3 categories of next-generation vaccines (definitions below). Each section ends with an overview of vaccines in the category – and each has a link to skip over that straight to the next news section. In addition, there are tables tracking mucosal vaccine trials and pancoronavirus vaccines on my personal website.

ICYMI:

• An introduction to self-amplifying mRNA, plus my compendium on getting ready for more mRNA fear-mongering.
• Check out my May 2024 post, “When will we get a sterilizing Covid vaccine?”

• Watchlist of featured vaccines
• Mucosal vaccine news
• Durable or “variant-proof” vaccine news
• Pancoronavirus vaccine news

• Addendum 1: List of authorized vaccines (with countries)
• Addendum 2: Definitions of vaccine types
• Addendum 3: Table of mucosal vaccines in clinical trials (here—off this blog)
• Addendum 4: Table of pancoronavirus vaccines with preclinical results (here—off this blog)

• Postscript: US Project NextGen funded trials

Watchlist of featured vaccines

This watchlist includes vaccines in advanced development, which currently appear to be progressing more than others, based on publicly available information. I have sorted them into several groups, starting with the most advanced prospects. Which vaccines make this list is very likely to change from month to month. For example, the Arcturus self-amplifying mRNA vaccine is not on this list, even though additional authorizations have been planned for it internationally. That’s because the impact of changes in the US have set it back, and there hasn’t been an update about the implications for further rollout.

I am featuring 9 vaccines this month:

[A] Vaccines in mid- to late-stage trials, with manufacturing partners or planned production facilities—3 vaccines (including 1 mucosal) from Japan, the US, and South Korea (VLP Therapeutics, Vaxart/Dynavax, DV&VX);

[B] Vaccine in advanced mid-stage trials—for people with immunocompromise, from the US (Geovax);

[C] A vaccine adapted from a Covid vaccine that has already been approved in South Korea (SKYCovione); and

[D] Vaccines in mid-stage trials with recent public progress—4 vaccines (all mucosal) from Canada, the US, and France.

A. Vaccines in mid- to late-stage trials with manufacturing prospects:

Self-amplifying mRNA vaccine from VLP Therapeutics Japan:

This development program has been moving rapidly, adapting the vaccine to emerging variants in Japan. It is a self-amplifying mRNA vaccine, which can be more durable than first-generation mRNA. (My explainer on this vaccine type here.) The developer, VLP Therapeutics, is based in the US and Japan. They have been receiving funding support from the Japanese government for this vaccine, and I do not know if there are plans for making the vaccine available in other countries. VLP Therapeutics has also received private backing, developing manufacturing facilities in Japan.

I’ve listed all the clinical trials for this vaccine in the following table. VLPCOV-1 targeted the original strain of Covid, VLPCOV-2 was adapted for the Gamma variant, and versions 4 and 5 were adapted to Omicron variants.

Results have been published for a phase 2 trial of VLPCOV-2, which was compared to an Omicron-adapted version of the BNT/Pfizer vaccine. The VLP vaccine had similar results, even though it had the disadvantage of not being adapted to Omicron.

At the end of March, a phase 1 trial was registered for a “universal” Covid version of the vaccine. This latest version of the vaccine is called VLPCOV-U-1, and it is a T-cell-inducing vaccine aimed at a part of the virus that has not mutated in new Covid variants. T-cell-inducing vaccines don’t rely on developing antibodies, but develop T-cells to eliminate virus-infected cells.

Over 10,000 people have been recruited to phase 3 trials for the Omicron versions. Given the speed at which this development program has been moving, it might not be long until we get the first phase 3 trial results.

(All records in my collection for this vaccine here.)

Phase	Trial status	Participants	Register record	Results reported
VLPCOV-1
1	Begun 2021; completed.	Booster dose in 45 adults.	jRCT2071210067
1	Begun 2022; completed.	Booster dose in 92 adults.	jRCT2051210164	August 2023
2	Begun 2022; fully recruited.	Booster dose in 300 adults.	jRCT2051220087
VLPCOV-2
1/2	Begun 2023; completed.	Booster dose in 96 previously vaccinated adults (phase 1); 323 adults in phase 2.	jRCT2051230005	February 2024 (Phase 1) February 2026 (Phase 2)
VLPCOV-4
3	Begun 2023; fully recruited.	Booster dose in 2,000 adults.	jRCT2051230141
3	Begun 2024; fully recruited.	Booster dose in 2,000 adults.	jRCT2051230178
VLPCOV-5
3	Begun 2025; fully recruited.	Booster dose in 6,200 adults.	jRCT2031240751
VLPCOV-U-1 (“Universal” Covid)
1	Begun 2026; recruiting in Japan.	Booster dose in 80 adults.	jRCT2051250250

Oral viral vector vacccine from Vaxart and Dynavax (USA):

This mucosal vaccine comes in tablets, and it is based on an adenoviral vector. Vaxart expects to release the 12-month results for the first 400 people in its large phase 2b trial by the middle of this year, with the first results for the other 5,000 people by the end of the year. Late last year the company announced that, pending positive phase 2b results, Dynavax will be their global manufacturing partner. Then at the end of year, drug manufacturing giant Sanofi acquired Dynavax.

I’ve listed their clinical trials in the following table. They have released so far from their phase 2a trial so far, indicating that the vaccine induced additional mucosal immunity in people who had previously been vaccinated with mRNA.

(All records in my collection for this vaccine here.)

Phase	Trial status	Participants	Register record	Results reported
1	Begun 2020; completed.	Booster dose in 40 adults.	NCT04563702	July 2022
2a	Begun 2021; completed.	Booster dose in 66 adults.	NCT05067933	Brief report: September 2022 press release.
2b	Begun 2024; fully recruited.	Booster dose in 5,400 adults.	NCT06672055	(Expected in late 2026.)

Virus-like particle vaccine from Stanford University and DX&VX (USA, South Korea):

DV&VX announced that they are accelerating this vaccine’s development, planning to start a global phase 2 trial early this year. They have indicated interest in developing a mucosal version of the vaccine. The developers at Stanford aimed for a low-cost vaccine stable at room temperature, that would not be vulnerable to changing Covid variants. It’s a ferritin-based virus-like particle vaccine, using nanoparticles to modify the proteins.

The developers at Stanford aimed for a low-cost vaccine stable at room temperature, that would not be vulnerable to changing Covid variants—another “universal” Covid vaccine. It is also expected to have yearly boosters.

Their clinical trial program is in the table below.

(All records in my collection for this vaccine here.)

Phase	Trial status	Participants	Register record	Results reported
1	Begun 2023; completed.	Booster dose in 121 adults (USA).	NCT05870839
1	Begun 2023; completed.	Booster dose in 130 adults (South Africa).	NCT05938075
2	(Expected in early 2026.)

B. Vaccine in advanced mid-stage trials:

Viral vector vaccine for people with compromised immune systems, from the City of Hope and Geovax

This is the only advanced next generation Covid vaccine designed for better protection of people with immunocompromise and others at high Covid-risk. (Arcturus is also running a phase 2 trial of their self-amplifying mRNA vaccine.) This is one of the vaccines that faced a setback when the US government canceled Project NextGen support. Geovax has reported that it is seeking partners to take the vaccine forward.

The City of Hope/Geovax vaccine has outperformed mRNA vaccine in people with immunocompromised in their trials: a table of their trials follows. The viral vector is modified Ankara virus (MVA).

(All records in my collection for this vaccine here.)

Phase	Trial status	Participants	Register record	Results reported
1 to 2	Begun 2020; completed Dec 2025	Booster shot (escalating doses) in 119 healthy adults	NCT04639466	Phase 1 (56 participants)
2	Begun 2021; fully recruited.	2 dose regimen in 63 adults with blood cancer who have received stem cell transplant or cellular therapy (compared with mRNA vaccine)	NCT04977024
2	Begun 2023; still recruiting for experimental arm only.	1 dose in 80 adults with chronic lymphocytic leukemia (CLL) (initially compared with mRNA vaccine, but control group discontinued because of lack of effect)	NCT05672355

C. Adapted version of an already-approved vaccine:

Protein subunit unit pancoronavirus vaccine from SK Bioscience (South Korea)

A phase 1/2 trial for 368 participants has only just started for this vaccine in Australia. However, as it is an adapted version of a Covid vaccine that had already achieved authorization (marketed for a time as SKYCovione), it begins with the advantage of an established research base that may speed it up down the line.

This vaccine was originally developed by the University of Washington in Seattle. The original vaccine was shown to provide some protection against other sarbecoviruses in animals, leading to the development of a pancoronavirus version of the vaccine.

(All records in my collection for the original version of this vaccine here, and for the pancoronavirus version here.)

D. Vaccines in mid-stage trials with recent public progress:

There are 4 mucosal vaccines in this group, that have yet to announce manufacturing partners:

• Aerovax: This aerosolized viral vector vaccine (adenovirus) is being developed by McMaster University in Canada. The phase 2 trial began recruiting participants in March 2025, and is still recruiting at McMaster. (All records on this vaccine here.)

• Castlevax: This intranasal viral vector vaccine (Newcastle disease) has been authorized in some countries in injected form. The vaccine was developed by the Icahn School of Medicine at Mt Sinai in New York. The phase 2 trial began dosing participants in November 2025, and is recruiting in Colorado and Massachusetts. (All records on the US development of this vaccine here.)

• CyanVac and Blue Lake Biotech: This is an intranasal viral vector vaccine (parainfluenza), and it was developed at the University of Georgia. A phase 2b trial for this vaccine was fully recruited by November 2025. There is a new preclinical report for this vaccine, discussed below. (All records on this vaccine here.)

• University of Tours and LovalTech: This is an intranasal protein subunit vaccine, developed with French government support. Phase 1 of a phase 1/2 trial finished dosing in May 2025, and LovalTech is seeking additional financial support: Phase 2 may not begin this year.

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Mucosal vaccine news

This month there were 6 preclinical reports on mucosal vaccines, including an intranasal live attenuated vaccine which is included in the “variant-proof” section below. I also did some housekeeping on the table tracking mucosal vaccines in clinical trials, checking for any developments I had missed—and there were several:

• There was a report in 2023 for a trial of 356 people comparing boosters of CanSino’s viral vector vaccine, Convidecia, either aerosolized or injected, with a booster of an inactivated vaccine. Both versions of Convidecia elicited stronger immune responses than the inactivated vaccine. Another of the trials registered for Convidecia did not proceed. Results have been reported for 16,700 people randomized in trials of Convidecia Air.

• Phase 1 trials for 2 vaccines were reported as fully recruited in November 2025—NIAID’s viral vector vaccine (murine pneumonia) and the viral vector vaccine (parainfluenza) from CyanVac and Blue Lake Technology; and

• A vaccine from China which has been named differently along its development had been listed as separate vaccines, and I merged these.

These are all marked with an asterisk (*) in the table.

Preclinical reports

• Intranasal viral vector vaccine from the University of Georgia and CyanVac/Blue Lake Technology (USA): This vaccine is one of the featured group in phase 2 trials discussed in the watchlist above. This new preclinical report is the fifth for this vaccine. (All records on this vaccine here.) The viral vector for this vaccine is parainfluenza virus 5 (PI5). This paper reports on tests of a version adapated to an Omicron variant (KP.2) in mice and hamsters, comparing it to the original vaccine version and no vaccination. Challenge tests were conducted in both species, with a variation in response: The adapted vaccine was similar to the original vaccine in mice, but induced stronger protection in hamsters.

• Intranasal nanoparticle vaccine from the University of São Paulo (Brazil): This is the first report for this vaccine. The vaccine includes 2 types of components, and was tested in a 3-dose regimen in mice (compared with no vaccine or non-antigen placebo). The vaccine protected the animals from severe illness in a challenge test with the original Covid strain, while some had low levels of viral load which were eliminated within 24 hours and mild symptoms. Signs of immunity remained strong after a year.

• Intranasal combined viral vector and protein subunit vaccine from Nankai University and the Guangzhou National Laboratory (China): This is the first report for this vaccine. It is based on Adenovirus 5 and a ferritin subunit. The vaccine was tested in mice with an injection followed by an intranasal booster, including Covid challenge. Compared to either the viral vector or subunit alone, the combination vaccine induced stronger immune responses more quickly, and protected the animals in the challenge test.

• Intranasal viral vector vaccine from the University of Alabama and Meissa Vaccines (USA): This vaccine reached clinical trial, but it’s future prospects are not clear. Meissa Vaccines was reported to be in financial difficulties in 2024, and their website was taken down around mid-2025. This new preclinical report is the second (All records for the vaccine here.) The viral vector for this vaccine is RSV, and 2 versions were tested in mice, including Covid challenge.

• Microparticle vaccine from the University of Konstanz (Germany): This new report is the second for this vaccine. (The first is here.) The vaccine includes PLGA microparticles and Riboxxim (a synthetic form of DNA developed for cancer treatment). An injection followed by an intranasal booster dose was tested in mice. Signs of immune response were detected in the respiratory tract as well as the blood.

Skip ahead to next news category

Mucosal Covid vaccine overview

• 5 mucosal vaccines are currently authorized for use, at least 1 in each of 6 countries. None have been authorized by a drug regulatory agency designated stringent, or listed, by WHO. However, each has been authorized by a regulator which has transitional WHO listing for vaccines.
• 36 mucosal vaccines have reached clinical trial, although some of the vaccines are no longer in development. The vaccines that have entered clinical trials are tracked in a table below. They are mostly viral vector vaccines.
• In addition to the 5 authorized mucosal vaccines, 6 have reached phase 2 trials, and another 2 have reached phase 2/3 trial.

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Durable or “variant-proof” vaccines

This month, there were 3 preclinical reports for vaccines in this category, including a mucosal vaccine. A review article was also published for the Geovax vaccine, and I discuss that in the featured vaccines section above.

Preclinical reports

• Intranasal live attenuated vaccine from the Friedrich Loeffler Institute, University of Basel, and Rocketvax (Germany, Switzerland): This is the second preclinical report for the vaccine, which aims to prevent Covid infection. (The first is here). The new report tests a single-dose version of the vaccine adapted to an Omicron variant (XBB.1.5). It was tested in mice and hamsters, including a co-housing experiment with Covid-infected hamsters to test for protection against infection. The developers reported that no co-housed animals became infected, outperforming mRNA vaccine.

• mRNA vaccine from the University of Naples Federico II (Italy): This is the first report for this vaccine. The vaccine has a pair of components: An antigen based on components common to the Delta and some Omicron variants, and a component designed to stimulate T-cell response. It was tested in mice as a booster after primary vaccination with an mRNA vaccine based on the original Covid strain only, and compared with a booster of an mRNA vaccine based on components of 3 variants of SARS-CoV-2 including the original strain. The developers concluded that their vaccine increased the breadth of immune responses.

• Combined viral vector and protein subunit vaccine from the National Clinical Research Center for Geriatrics, Sichuan (China): This is the first report for this vaccine. The vaccine combines viral vector (Adenovirus 5) and protein subunit components, and it was tested in mice. Signs of immune response remained high at over 6 months. It was also tested as a booster after mRNA vaccination.

Skip ahead to next news category

Durable or “variant-proof” vaccine overview

Note: This is a rather vague category, including vaccines that aim to be more durable. I’m not sure how many can be classified as aiming to be “variant-proof”.

Authorized vaccine:

There is 1 authorized vaccine in this category, and it has been authorized by several drug regulatory authorities designated by WHO has stringent, and tested against an mRNA vaccine (Kostaive):

• LUNAR-COV19 (USA), trade name Kostaive: This self-amplifying mRNA vaccine was authorized in Japan in November 2023, with rollout in October 2024. It was authorized for Europe in February 2025, and in the UK in January 2026.

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Pancoronavirus vaccine news

This month, there were 2 preclinical reports for vaccines in this category. The first is currently targeted to MERS, with plans to test it for other coronaviruses. The second was previously available as a preprint.

Preclinical reports

• Peptide subunit vaccine from ConserV Bioscience and the University of Maryland (UK, USA): This is the first report for this vaccine, which is based on components of the MERS vaccine. It was tested in mice, including MERS challenge: 90% of the vaccinated mice survived. The developers discuss extending investigations of this vaccine to other viruses that affect human and other animals from Orthocoronavirinae, a category of viruses which include betacoronaviruses—though it’s not clear if they will be testing it for Covid.

• Self-amplifying mRNA vaccine with a protein subunit booster from Tiba Biotech (USA): This report was previously available in preprint (October 2025). It is the first publication for a pair of vaccines targeting variants of SARS-CoV-2 and MERS. Several versions of the regimen were tested in mice and hamsters, with the samRNA-prime and protein subunit booster induced the strongest and most durable immune responses, including to Covid variants not included in the vaccines. It was tested in mice and hamsters.

Pancoronavirus vaccine overview

A table below this post keeps track of vaccines I’ve added to this category so far that have publicly available preclinical results. Of these vaccines, 8 have reached phase 1 clinical trials, and 1 has reached phase 2. Some of them have released some results, and they are marked *:

• * CoronaTcP (Gylden Pharma, UK/US) – protein subunit. (Note: This vaccine was previously called PepGNP-SARSCov2, and the manufacturer was previously called Emergex.)

• DIOSynVax (Cambridge University spin-off, UK) – mRNA.
  
  
• Duke University (USA) – protein subunit.
  
  
• INSERM/Ennodc (formerly LinkInVax) (France) – protein subunit.
  
  
• Osivax (France) – protein subunit.
  
  
• SK Bioscience (South Korea) – protein subunit.
  

• * VBI Vaccines (Canada) – eVLP. [This company announced bankruptcy in late 2024.]

• * Walter Reed Army Institute of Research (WRAIR, USA) – protein subunit.

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Addendum 1: List of authorized next generation Covid vaccines (with countries)

There are 7 authorized next-generation Covid vaccines. Only one has been approved by drug regulatory agencies designated stringent, or listed, by WHO – in bold; the others have all been approved in at least one country by a drug regulator WHO has listed with transitional status for vaccines. I’ve listed the vaccines in 2 categories, in order of date of first authorization (or initial approval).

Mucosal:

• Razi-Cov Pars (Iran), intranasal protein subunit vaccine: Iran (October 2021).
• Sputnik (Russia), intranasal viral vector vaccine: Russia (April 2022).
• Convidecia (China), inhaled viral vector vaccine: China (September 2022), Morocco (November 2022), Indonesia (March 2023).
• iNCOVACC (USA/India), intranasal viral vector vaccine: India (September 2022).
• Pneucolin (China), intranasal viral vector vaccine: China (December 2022).

Durable or “variant-proof”:

• Gemcovac (India), self-amplifying mRNA vaccine: India (June 2022).

• Kostaive (LUNAR-COV19) (USA), self-amplifying mRNA vaccine: Japan (November 2023), European Union (February 2025), UK (January 2026).

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Addendum 2: Definitions of vaccine types

• Mucosal vaccines: These enter the body the way the virus does – through mucosal tissues. It’s hoped that provides defence against infection. They can be administered via different routes – squirts or drops in the nose, inhaled through the mouth through a nebulizer (similar to an asthma medication), or in tablet, capsule, or sublingual form.

• Pan-SARS-CoV-2 or “variant-proof” vaccines: These aim to provide protection against any variant of the coronavirus that causes Covid-19.
  

• Pancoronavirus vaccines aim to protect against coronaviruses more broadly – sometimes called “universal coronavirus vaccine.” These vaccines can be targeted to:
  
  – the “subgroup” the 2 SARS viruses came from (the sarbecovirus subgenus),
  
  – coronaviruses from the next level up (the genus, betacoronavirus, which includes MERS as well as the sarbecoviruses), or
  
  – up to the whole coronavirus family, which has 4 genuses, including betacoronavirus and alphacoronavirus (with more common cold viruses).
  
  I classify a vaccine as a pancoronavirus one when the developers are explicitly targeting coronaviruses more broadly than SARS-CoV-2 in the design of the vaccine, and have tested for signs of response to non-SARS-CoV-2 coronavirus(es) (or clearly plan to).

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You can keep up with my work at my newsletter, Living With Evidence. And I’m active on Mastodon: @hildabast@mastodon.online and less so on BlueSky (hildabast.bsky.social).

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Disclosures: My interest in Covid-19 vaccine trials began as a person worried about the virus, as my son was immunocompromised: I have no financial or professional interest in the vaccines. I have worked for an institute of the NIH in the past, but not one working on vaccines. More about me.

The cartoon is my own (CC BY-NC-ND license). (More cartoons at Statistically Funny.)

For details on how I track Covid vaccine progress, see my background post. Notes on my collection of studies are here. The collection is in a public Zotero library you can dig into here.

Previous update posts specifically on next generation Covid vaccines prior to this monthly series (beginning May 2023):

1. Mucosal vaccines (March 2022)
2. Pan-SARS-Cov-2 and pancoronavirus (July 2022)
3. Mucosal vaccines (July 2022)
4. Mucosal vaccines (September 2022)
5. Mucosal vaccines (April 2023)
6. Pancoronavirus vaccines (April 2023)

All my posts on Covid vaccines, beginning from March 2020, are tagged here.

All previous Covid-19 posts at Absolutely Maybe

My posts at The Atlantic and at WIRED.

Postscript: US Project NextGen funded trials

Mucosal vaccines:

• Phase 1 for MPV/S-2P, the intranasal viral vector vaccine developed by the NIH’s National Institute of Allergy and Infectious Diseases (NIAID). This trial for 60 participants began recruiting in July 2024, and finished recruiting by early 2025.

• Phase 2b for the oral viral vector vaccine from Vaxart (trial start announced at the end of September 2024; trial registration here) – further recruitment for this trial was cancelled, though followup will be completed for the participants already dosed (around 5,000). The company has a deal with Dynavax to take the vaccine forward, depending on phase 2 trials.
• Phase 2b for the intranasal viral vector vaccine from CyanVac/Blue Lake Biotech (trial started in December 2024, trial registration here) – no recent news on this trial.

• 2 trials are apparently not going ahead: A Phase 2b (“mini-efficacy”) for the intranasal protein subunit vaccine from Castlevax – this grant was paused and may be terminated. Castlevax has since registered a far smaller phase 2a trial with some similar methodological features. Another for the intranasal live attenuated vaccine from Codagenix had not apparently started.

Durable or “variant-proof” vaccines:

• Phase 1 for STX from Capricor (trial began dosing participants in August 2025). Capricor announced in November 2025 that the trial is ongoing.

• Phase 1 for TNX-1800 from Tonix (aiming for lifelong immunity) (planned to go into clinical trial in 2024 – no recent news);

• Funding was terminated for the Phase 2b (“mini-efficacy”) trial for GeoVax (viral vector vaccine).

Note: Gritstone Bio was originally in line for a phase 2b trial for their self-amplifying mRNA vaccine. However, the company declared bankruptcy and in January 2025, their assets were sold.

Pancoronavirus vaccines – presumed canceled:

• CoronaTcP (Gylden Pharma, UK/US) – protein subunit.
• Unnamed (PopVax, India) – mRNA.

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