Image copyright Reuters Image caption Unvaccinated older adults are not allowed to return to Moscow hospitals
Moscow authorities have ordered the unvaccinated over-60s and the pregnant to stay home for a year.
Health officials say both groups are susceptible to serious health problems following the return of diseases like measles and rubella.
Moscow’s regional health department says unvaccinated adults without health insurance must be enrolled in a vaccine-only scheme.
The scheme will be voluntary for those aged 65 or over.
A single vaccine will cost 6,500 roubles (£78) for older adults. That will cover a number of diseases including measles, rubella, varicella, hepatitis A and b, mumps, influenza and meningitis.
About 3% of the region’s 5.1 million population is aged 60 or over.
“Resistance to vaccinations is fuelled by these conditions,” deputy regional director Viktor Alyodinov said in a statement, according to Russian media.
“The virus can be revived, can be resistant to various vaccines. That is why the only way is a total prevention of these problems. The illnesses we have today can still be reoccured today or tomorrow.”
Correspondents say there are concerns over the transmission of diseases in Moscow, particularly for those living in one of the city’s large apartment blocks.
There are also fears that people who might be resistant to some vaccines can take them for granted and miss out on other vaccines.