As of April 16, 2021, information about blood clots in people vaccinated with the Sputnik V and the CanSino COVID-19 vaccines come from news articles and press releases.
Here is a link to an April 14, 2021 article in MedExpress that discusses the Sputnik V vaccine.
A statement ...
From an article in JAMA
When the [Pfizer and Moderna] vaccines were first tested, a relatively weak immune reaction was found within a few weeks after people received the first dose of vaccine, followed by a strong reaction when a second dose was given.
Multiple doses are not uncommon in vaccinations. Shingrix, a shingles vaccination is also two dose, as ...