No, they are not. But let's look into it to see why people believe this, and why such an idea is a bad one.
The History of this Claim
On the 14th of February, 2022, Russia invaded Ukraine. Almost immediately after this happened, a Twitter user named @WarClandestine (who believes in conspiracies like the QAnon idea that there was massive voter fraud in the 2020 US presidential election) wrote:
"Russia is targeting U.S. biological weapons labs in Ukraine invasion... China and Russia indirectly (and correctly) blamed the US for the [Covid-19] outbreak... and are fearful that the US/allies have more viruses (bioweapons) to let out."
The only problem is that the U.S. doesn't operate any biolabs of any kind in Ukraine. While Ukraine does have its own biolabs, these labs are not used to create bioweapons. Furthermore, they have mainly been used to prevent the effectiveness of such weapons since The Cooperative Threat Reduction Program's implementation after the fall of the Soviet Union.
According to many experts, as well as the United Nations, Ukraine's biolabs do not even have the capability to create any form of biological weapon. The claim that Ukraine biolabs are in any way suspicious comes from Russian propaganda that started as far back as 2018 to try to make "the west" look as bad as possible. Snopes have fact-checked this earlier claim and showed it to not hold any water.
So the claim started off as unfounded Russian propaganda. It was then picked up and changed by a group of conspiracy theorists named QAnon, who believe "the Hollywood elite" and rich Democrats are drinking the blood of children. They apparently do this because said blood apparently contains "Adrenochrome" which is believed without evidence to provide immortality.
From then, it was picked up and not verified before being broadcast by the conservative media organization Fox News via one of their hosts: Tucker Carlson. And that is how the conspiracy theory went from Russia stating that Ukrainian biolabs are sickening Ukrainians, to the idea that US-ran biolabs in Ukraine are modifying the COVID-19 virus (SARS-CoV-2) as a bioweapon to attack Russia.
Russia is currently ordering Russian TV news programs to air the Tucker Carlson segment accusing the US government of these biolabs as a way to push more anti-US propaganda. This shows how dangerous the spread of misinformation can be.
So in the end, this whole idea is just a crazy conspiracy theory backed by propaganda that has no legs to stand on. But even if it were true, would using SARS-CoV-2 as a bioweapon even make sense? Let's take a deep dive into that.
SARS-CoV-2 would be a terrible bioweapon.
The idea of SARS-CoV-2 being bioengineered in the lab as a bioweapon has been around since the start of the COVID-19 pandemic. Many people even support the theory that it might have been released deliberately. That said, there is no evidence to support such a belief. The best conclusion we have been able to come to was that the virus may have escaped accidentally, but even that claim is dubious. Recent research supports the idea that it came from a live-animal market in Wuhan via more natural means.
Getting that out of the way, is SARS-CoV-2 even a good candidate for a bioweapon? Not really. At least, not according to the history of the US's biological weapons program that was dismantled in 1975 due to lack of evidence for a good biological weapon, and due to risk of unnecessary harm to civilians and allied troops. Other experts also seem to echo this idea, especially when it comes to the current virus affecting the population.
In order to make a good bioweapon, according to US defense expert and infectious disease physician Mark Kortepeter, many things need to be taken into account. Any virus or bacteria used would have to be easy to access, contagious, stable, need only a small amount to spread, with a large portion of infected becoming ill, and thus causing widespread panic in the country. But most importantly, the people using the bioweapon should be protected from its effects.
A bioweapon that is highly infectious and likely to spread far and spread quickly in a world as interconnected as we have today would be a bad idea. We would basically be sickening ourselves as much as we would sicken the people we are against.
SARS-CoV-2 also has many other issues, according to Dr. Kortepeter, such as not being stable in outdoor environments, especially in the sun. Also, most people infected are asymptomatic, so it would be less useful on that front. So, based on this information, SARS-CoV-2 would make a rather terrible bioweapon.
The main point here is to not trust every source you come across and to do your own evidence-based research before spreading an unproven claim such as the idea that the US has bioweapon facilities in Ukraine. By the way, even many community colleges have biological labs, so the possession of a "biolab" isn't cause for immediate condemnation and fear.
Check out the video below for the full 2-hour UN meeting which showed a lack of evidence for the US biological weapons labs in Ukraine.