If Unz is right, then it appears it was likely the US that attempted to use it as a bioweapon against China. How did it jump to Iran and nowhere else so quickly?

Regarding the bioweapon angle, if the "vaccines" are leaky, then these "vaccines" are only going the improve the lethality of the virus.

https://en.wikipedia.org/wiki/Marek%27s_disease#Prevention

The first Marek's disease vaccine was introduced in 1970. The disease would cause mild paralysis, with the only identifiable lesions being in neural tissue. Mortality of chickens infected with Marek's disease was quite low. Current strains of Marek virus, decades after the first vaccine was introduced, cause lymphoma formation throughout the chicken's body and mortality rates have reached 100% in unvaccinated chickens. The Marek's disease vaccine is a "leaky vaccine", which means that only the symptoms of the disease are prevented.[12] Infection of the host and the transmission of the virus are not inhibited by the vaccine. This contrasts with most other vaccines, where infection of the host is prevented. Under normal conditions, highly virulent strains of the virus are not selected. A highly virulent strain would kill the host before the virus would have an opportunity to transmit to other potential hosts and replicate. Thus, less virulent strains are selected. These strains are virulent enough to induce symptoms but not enough to kill the host, allowing further transmission. However, the leaky vaccine changes this evolutionary pressure and permits the evolution of highly virulent strains.[13] The vaccine's inability to prevent infection and transmission allows the spread of highly virulent strains among vaccinated chickens. The fitness of the more virulent strains is increased by the vaccine.

Based on the evidence I've seen that vaccinated people are still being infected with and transmitting SARS-COV-2, that leads me to conclude that these mRNA vaccines are leaky.

https://www.medrxiv.org/content/10.1101/2021.07.31.21261387v1

Here we use this viral load data to compare the amount of SARS-CoV-2 present in test-positive specimens from people who self-report their vaccine status and date of final immunization, during a period in which the delta variant became the predominant circulating variant in Wisconsin. We find no difference in viral loads when comparing unvaccinated individuals to those who have vaccine “breakthrough” infections.