Unscheduled Polio Vaccinations Rise in North Caucasus Amid Worries of Local Transmission

In February, extra unscheduled vaccinations against polio began in four regions of the North Caucasus as health authorities faced an unsettled epidemiological situation. Dagestan, Ingushetia, Karachay-Cherkessia and Chechnya reported the lowest vaccination coverage in the country. As a consequence, acute flaccid paralysis cases started to appear in these areas, most often traced to the polio virus. A Russian news outlet raised questions about the possibility of an epidemic in Russia [Lenta.ru].

Historically, the USSR experienced a large polio epidemic in the mid-20th century. Data from the period show that thousands fell ill annually in the 1950s, with the most recent major outbreak recorded in Chechnya in 1996, a time when vaccines were broadly neglected due to ongoing conflicts [Attribution: historical records].

There is still no precise tally of polio cases following the February outbreak in the Caucasus. Regional health officials continue to monitor the situation and emphasize uncertainties in case counts during the crisis period [Lenta.ru].

Muminat Dzhabrailova, deputy chief physician responsible for epidemiological problems at the republic’s Center, noted that last year 44 cases of suspected acute limp paralysis were reported in Dagestan. The affected children ranged from 3 months to 11 years old.

Some of these children were not vaccinated, while others did not follow the recommended vaccination schedule, according to officials on the ground.

Zalimkhan Omariyev, acting head of Dagestan’s Rospotrebnadzor department, warned that regular polio circulation has taken hold in the region, explaining that the disease is asymptomatic in about 90 percent of cases.

He stressed that one in ten cases can present the neurological symptoms associated with polio in children, highlighting the potential severity despite many silent infections [Lenta.ru].

The publication suggests that the suspected emergence of polio in Russia aligns with a sharp rise in vaccine skepticism in the Caucasus. In Dagestan, the number of unvaccinated children has grown fivefold over the past six years, according to the report. Authorities acknowledge that the true number of individuals refusing vaccines could be higher than official figures indicate.

Elena Pokrovskaya, the Karachay-Cherkess representative of Rospotrebnadzor, said that in four North Caucasus regions, fewer than 95 percent of the population is vaccinated. Such a marked drop in coverage raises the risk of virus spread continuing until a new epidemic is averted. Migration flows are also cited as a possible route for importing the virus [Lenta.ru].

In the Russian Federation, polio vaccination is part of the National Immunization Program. The schedule includes vaccines at three, four and a half, and six months of age, with revaccination at 18 and 20 months and again at six years. The first two doses use the inactivated polio vaccine (injected), followed by the live polio vaccine in later doses. The inactivated vaccine is entirely safe and produces immunity, though often less durable than live vaccines in some contexts [Source: immunology guidelines].

Unscheduled vaccination remains possible when epidemiological risks are identified, with authorities citing the need to respond quickly to emerging threats.

Polio damages the nervous system and spreads via the fecal-oral route, typically through contaminated hands, food, or water. Ancha Baranova, a biologist with a Ph.D. and a professor at the George Mason Institute in the United States, described polio as a disease closely tied to hygiene. She added that the incubation period ranges from three days to about a month, often one to two weeks until symptoms appear.

The typical early signs include fever, headache, muscle pain, and sore throat, with paralysis appearing in rare instances. Baranova emphasized that most infections do not involve stroke-like symptoms, but about five percent of infections can lead to partial or complete paralysis, respiratory failure, or death, with young children particularly at risk [Lenta.ru].

Polio has a long history, known to ancient civilizations in Rome, Greece, and Egypt. In 1988, the Global Polio Eradication Initiative was launched, and by the mid-20th century polio was treated as a major global threat. Thanks to a worldwide vaccination effort reaching billions of children, the incidence of polio declined by more than 99 percent. The Russian Federation has maintained a polio-free status, according to official health authorities [Lenta.ru].

One possible source of outbreaks is wild poliovirus, which has been nearly eliminated in nature. Only one of the three original wild types remains, detected in limited areas of Afghanistan and Pakistan [Lenta.ru].

The coronavirus era demonstrated how quickly a virus can spread globally with modern connectivity. Russian health experts note that in 2022, twenty-one people in the country were infected with wild polio type 1 [Lenta.ru].

A second risk comes from vaccine-derived polioviruses. Biologist Antonina Oblasova warned that mishandling the oral polio vaccine (OPV) could cause the vaccine virus to replicate in the gut and spread in communities. If the virus continues to circulate among both vaccinated and unvaccinated groups, mutations could eventually lead to paralysis again. After vaccination, it is important to minimize contact with unvaccinated individuals and follow recommended precautions [Lenta.ru].

In light of the situation in the Caucasus, Darya Kartasheva-Eberts, a doctoral immunologist at the Pasteur Institute in Paris, urged residents of Dagestan, Ingushetia, Chechnya, and Karachay-Cherkessia to participate in a comprehensive vaccination campaign. She also encouraged residents of other parts of Russia to maintain the vaccination schedule and not neglect immunization.