June was a relatively slow news month for next generation Covid vaccine development. So I took the opportunity to simplify the structure…
Bumper Month of Clinical Trial News to Ring Out This Vax Series
Image credit
Image by Hilda Bastian, CC BY-NC-ND 4.0
Before I get to the bumper crop of recent clinical trial news, there is news about this monthly update. This is the last one that will appear here at PLOS. PLOS has been a wonderful host to an independent blog network for years, and I am very grateful to them for including Absolutely Maybe. That network is winding up this month—I’ll be uploading a farewell post shortly.
That left me with a decision to make about keeping up with the next generation Covid vaccine news. I know a lot of people are as interested in these updates as I am. So rather than calling it quits, I am going to try to continue it as a free-standing, reader-supported project. It has always been difficult to wedge this work into the format of a blog post, so there are advantages to this for me and for readers.
If you’re a regular reader of this series who subscribes to the free version of the new Tracker, you may not notice much difference—the updates will be much like this one. My online collection of vaccine records—now with over 3,400 entries—remains freely accessible.
If you are able to support the Tracker with a paid subscription, though, as well as enabling this work to continue, you will see a lot more analysis. There are several new overview and tracking features, and I have done a lot of house-keeping on the vaccine tracking tables that used to be part of these posts—including sorting those vaccine trial programs that are inactive from those with trial progress.
Now let’s dig into this month’s vaccine news. There are reports of clinical trial results for 2 mucosal vaccines, another intranasal vaccine has gone into a phase 1 trial, and 4 clinical trials for nextgen Covid vaccines have reached full recruitment or completion. There are also results from 2 Covid human challenge studies, and another has started recruiting. In addition, a company has added an inhaled combined Covid/influenza vaccine to its pipeline. There is some sad news, too, with one vaccine shelved. There are also 7 preclinical reports.
As usual, I group vaccines in 2 or 3 categories in some parts of this post. There are definitions for these categories in an appendix.
 | Check out the new NextGen Covid Vax Tracker! |
- Watchlist update and other news
- New clinical trial results
- Clinical trial progress
- Preclinical reports
- Details of vaccines featured in the watchlist (now at the new Tracker)
- Appendix: Definitions of vaccine types
Watchlist updates and other news
There is lots of good news, and a bit of bad news here this month.
New results from clinical trials of 2 vaccines have been released—including for one on the watchlist: Vaxart’s oral vaccine (USA), and the intranasal vaccine from Intravacc in the Netherlands. I discuss those results in the following section. Plus, the phase 2 trials for 2 featured vaccines from the US are fully recruited (Castlevax) or completed (CyanVac / Blue Lake Technology).
In other news, Ocugen, has a combined influenza (quadrivalent) and Covid inhaled vaccine in their pipeline, with plans to progress it to clinical trial. This US company currently has an inhaled Covid-only vaccine in a phase 1 trial. The vaccine is the viral vector vaccine developed in the US by Washington University in St Louis—and it is also the basis of iNCOVACC, which has been authorized in India. (All records in my collection for that vaccine’s original development in the US are here.)
Finally in watchlist news, the unhappy development: My featured vaccine watchlist is now down to 8 vaccines—the City of Hope / GeoVax viral vector vaccine for people with compromised immune systems is not going ahead. One of the trial participants let me know they had been told that the current environment in the US meant the vaccine was not viable for GeoVax. GeoVax has not made a public announcement as far as I am aware, but the Covid vaccine is no longer listed on their pipeline. Given it was developed for people who get far less benefit from current vaccines, this is very sad news.
It is possible that the watchlist could expand again in the near future, as some vaccines have been moving relatively quickly through early-stage clinical trials.
Human challenge study news
The MUSICC Consortium is doing the preparatory work needed to be able to run human challenge trials for mucosal vaccines. This month, they published 2 sets of results (in preprints).
The first is an extension of an early Covid human challenge study in the UK. The first publication from this study reported on 36 participants. This was testing the original version of SARS-CoV-2. The new preprint reports on 48 people in 5 challenge dose groups, most of whom had previously been Covid-vaccinated. Quantifiable shedding of the SARS-CoV-2 virus was detected in 48% of participants. None had severe illness, and there were no serious adverse events. The preprint analyzes correlates of infection.
The second preprint has the first results from a study testing human infection with a version of a Covid variant. This is the COVHIC002 study from the UK, based on varying doses of the Delta variant. Their goal was to achieve a rate of well-tolerated infection from the lowest possible dose in more than half of the 46 participants.
None of the 22 people in the lowest dose group were infected. Of the 24 inoculated with the highest dose of the virus, 6 remained uninfected. After screening, the team challenged 18 of the participants again: 6 of them met the criteria for infection (33%). Of the 24 finally, 12 remained uninfected—6 of the participants had a transient infection (5 from the group with the second challenge).
There were no serious adverse events, and infections were mild to moderate. After 12 months, no one showed signs of long Covid.
Although they did not reach their 50% infection rate goal with this version, the researchers learned more about the biomarkers of protection against infection in people who have been previously vaccinated or had Covid infections. The UK team is now focused on studying versions based on Omicron. They began a study with Omicron BA.5 in 2024, which was fully recruited by May this year.
The UK MUSICC team started recruiting for a second Omicron study this month. The new study is called COVHIC003, and it is testing a version based on the Omicron EG.5.1 virus in 38 people in the UK (London, Oxford, Southampton). The trial registry entry for this study is here, and MUSICC’s information for potential participants is here.
New clinical trial results
Phase 1 trial results for the intranasal OMV vaccine from Intravacc (Netherlands)
This vaccine is OMV-based. An OMV is a non-infectious, outer membrane vesicle shed from bacteria—like a shipping container from the cell—that can be recognized by the immune system. The OMV is used to transport the vaccine antigen.
The developer, Intravacc, has been going through a major transition since the phase 1 trial for the vaccine was registered in 2022. Intravacc used to be government-owned: It was formerly the Netherlands Vaccine Institute. It was privatized, then sold in 2024 (to FDI)—the year that the trial was fully recruited in Australia.
This month, the results of the trial were published. The primary focus of the trial was evaluating the safety of the vaccine in this first-in-human study. There were 40 participants who were randomized to one of 5 groups: a low or high dose the vaccine, a corresponding low or high dose of OMV alone, or placebo. Participants had to either have been previously vaccinated with another Covid vaccine, or have had a confirmed prior infection with SARS-CoV-2. They received 2 doses by nasal spray.
The developers concluded that the vaccine was well-tolerated, with none of the 26 participants in the vaccine groups reporting a severe adverse reaction, and a few reporting moderate reactions. However, a participant in the high-dose vaccine group had an adverse reaction rated severe (increased blood creatine) that resolved without needing treatment. The most common adverse reactions reported were mild pain in the nose/throat and mild or moderate headaches (about a quarter of participants).
This trial was not big enough to assess the vaccine’s efficacy, but signs of both systemic and mucosal immune response were tested. Participants receiving the higher dose vaccine showed higher immune responses than those in the lower dose group.
No news yet on whether Intravacc will be progressing this vaccine to phase 2.
Results from phase 2b safety trial of the oral vaccine from Vaxart (USA)
The phase 2b trial for this vaccine was funded by Project NextGen, in 2 parts. The first was a safety study with 400 participants, followed by a 5,085-participant efficacy trial. This month, the company issued a press release with some results from the safety study.
The 400 previously-vaccinated participants were randomized to vaccines based on the Omicron XBB.1.5 variant—either the Vaxart tablet or a booster injection of the BNT/Pfizer (Comirnaty). Vaxart reports that there were no serious or severe adverse events in either arm of the trial. The most common systemic adverse reaction in both groups was malaise/fatigue, for 20.9% in the Vaxart group and 35.2% in the BNT/Pfizer group. The vaccines had similar efficacy results, but this part of the trial was not big enough to confirm efficacy outcomes. (The company hopes that their vaccine will be more durable, providing protection for a year.)
The company expects to see results for the full phase 2b trial by the end of this year—testing vaccines based on the KP.2 variant. If the results meet their expectations, DynaVax would take the vaccine on to a phase 3 trial. For more detail on this vaccine’s progress, see the summary at the new Tracker. (All records in my collection for this vaccine here.)
Clinical trial progress
This month in this section, a phase 1 trial for another mucosal vaccine was registered. It is the 37th mucosal vaccine to reach clinical trial. Also this month, trials for 4 vaccines reached full recruitment or completion.
In other news, for those interested in the completed trial at the NIAID (NIH) for an intranasal viral vector vaccine based on murine pneumonia (called MPV/S-2P)—the trial registry record now has the trial’s protocol, statistical analysis plan, and informed consent form. (No results reported yet.)
Another intranasal Covid vaccine going into clinical trial
The 37th mucosal Covid vaccine to reach the clinical trial phase is an intranasal live attenuated vaccine from RocketVax (Switzerland). The vaccine was developed by the Freie Universität Berlin in Germany, and the phase 1 trial will be in the US. The trial registry record is here.
This trial has a planned start next month. The vaccine will be administered via nasal spray. No word yet on where the trial will be located, but the contact details are for the Baylor College of Medicine in Houston (details here).
Recently fully recruited or completed
Mucosal vaccines:
The second phase 1 trial for the intranasal viral vector vaccine from Rokote Laboratories (Finland) is fully recruited.
The phase 2 trial for the intranasal viral vector vaccine from Castlevax (USA) is fully recruited. This is one of vaccines featured on the watchlist. The vaccine was developed by the Icahn School of Medicine at Mt Sinai in New York, based on Newcastle Disease Virus. An injected version has been authorized in several countries. (All records on the US vaccine here.)
The phase 2b trial for the intranasal viral vector from CyanVac/Blue Lake Technology is now complete. This is another one of vaccines featured on the watchlist. It was developed at the University of Georgia. (All records on this vaccine here.)
Pan-coronavirus vaccine:
The phase 1 trial for the protein subunit vaccine from Gylden Pharma (formerly Emergex) (UK/USA) is now fully recruited (press release). This vaccine aims to protect against betacoronaviruses (the group that includes Covid, the original SARS, and MERS). The trial was funded by US Project NextGen.
Preclinical reports
Mucosal vaccines
Intranasal and inhaled viral vector vaccine from Chengdu Kanghua Bio and CAS Key Laboratory of Pathogen Microbiology and Immunology (China): This is the second preclinical report for this vaccine. (The first is here.) The vaccine is based on a chimpanzee adenovirus (AdC68) and the Delta variant. It was tested in mice.
Intranasal viral vector vaccine from Tsinghua University, Beijing (China): This is the first report for this pan-coronavirus vaccine, based on SARS-CoV-2 and the original SARS. It was tested in mice and hamsters.
Durable or “variant-proof” vaccine
Protein subunit vaccine from Stanford University (USA): This is the third preclinical report for this vaccine. It is based on polymer-nanoparticle hydrogels, and was tested in mice and non-human primates. (All records here.)
Self-amplifying mRNA vaccine from Emory University (USA): This is the second preclinical report for this vaccine. (The first is here.) The developers used rare epitope suppression and a complex antigen pool to create a “wobble vaccine.” It was tested in mice.
Pancoronavirus vaccines
A preclinical report for a mucosal pancoronavirus vaccine was included above.
Protein subunit vaccine from INSERM Vaccine Research Institute and Ennodc (formerly LinKinVax) (France): This vaccine against sarbecoviruses is in a phase 1 and a phase 1/2 trial. In this new report, the vaccine is tested in non-human primates. (All records for this vaccine here.)
DNA vaccine from DIOSynVax (UK): This vaccine against betacoronaviruses has been tested in a phase 1 trial. I added 2 preclinical reports—a report from this month, and a preprint from October 2025 that I had missed. (All records here.) In the new report, the vaccine was tested in mice. The 2025 preprint also reports on tests in mice, as well as epidemiological modelling.
Appendix: 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).
You can subscribe to my NextGen Covid Vax Tracker here, and keep up with my work at my newsletter, Living With Evidence. And I’m active on Mastodon: @hildabast@mastodon.online and 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 the Tracker. 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):
- Mucosal vaccines (March 2022)
- Pan-SARS-Cov-2 and pancoronavirus (July 2022)
- Mucosal vaccines (July 2022)
- Mucosal vaccines (September 2022)
- Mucosal vaccines (April 2023)
- 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.