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Why are there so few reported COVID-19 cases in Russia?

Source: Meduza

Note: The text below was published on March 6, 2020, and this is a rapidly developing situation.

The number of COVID-19 cases detected per day outside of China has long surpassed the recorded infection rate within Chinese borders. Nonetheless, between January 1 and March 5, 2020, Russia reported only four confirmed cases of the disease [Update: as of March 13, that number reached 45]. Only one of the four cases was found in Moscow, the second-largest city in Europe after Istanbul. Meanwhile, in Italy, France, and Germany, there were 3,089, 337, and 444 confirmed cases respectively as early as March 5 (updated figures are available here). This is despite the fact that the number of passengers who have traveled to those countries from China by air is comparable to the number traveling to Russia. While it’s impossible to say with certainty how this disparity arose, it is possible to offer a few potential explanations. Whether you believe them is up to you.

Hypothesis 1: Russia closed its borders fast enough that almost nobody infected with the virus could get in

The Russian government first increased its control over individuals arriving in the country from China on January 23, 2020, but it did not limit any means of transport until January 31. On that day, Russian officials closed off direct trains from Moscow to Beijing and closed its ground border with China to foot traffic and automobiles.

By then, 9,923 cases of COVID-19 had already been registered worldwide, both in China and in Taiwan, Singapore, Australia, the United Kingdom, and other countries. Even in Finland, which has a very small interchange of transit passengers with China and a large one with Russia, had registered cases. All this means that at least in theory, the new coronavirus had every opportunity to enter Russia before transportation to and from China was limited. In fact, it did just that: The first two infections recorded in Russia were detected on January 31 in two Chinese citizens traveling as tourists.

Hypothesis 2: At first, Russia just got lucky, and then limits at the border did their job

Despite Russia’s suspension of rail and auto traffic with China and its February 18 ban on Chinese citizens entering Russia at all, air traffic between the two countries has continued: Russians can go to China and come back.

Of course, people are coming down with the new coronavirus in plenty of other countries, too. Seventy-seven people are reportedly dead in Iran; assuming a (conservative) fatality rate of one percent for the illness and a two-week infection period, one can guess that there were 5,000 – 10,000 people infected in the country two weeks ago. However, Russia only introduced aviation limits with Iran on February 28, by which time that number had probably doubled. Similar reasoning applies in South Korea (2,337 recorded cases by February 28), Italy (888 cases), Singapore (93 cases), and other countries where Russia did not introduce any limits at all.

All this means the new coronavirus had ample opportunity to enter Russia after February 1 as well as before it, and with a few insignificant caveats, those opportunities remain open to this day. Whether they allow the coronavirus to take hold in Russia is another question.

Hypothesis 3: Russia managed to find everyone carrying the virus

Rospotrebnadzor, Russia’s consumer welfare agency, publishes a daily bulletin tracking its efforts to combat the coronavirus epidemic. That bulletin indicates that since January 31, when Russia directed all air traffic from China to Moscow’s Sheremetyevo airport, 382,155 individuals arriving from China have been examined, and 130 of them were found to have symptoms of infectious diseases. When Meduza requested comment, Rospotrebnadzor indicated that all of those individuals were isolated, but none were found to have the new coronavirus. Isolated cases of the flu and other infections were detected instead.

This all sounds well and good, but there may have been false negatives in testing (see below), to say nothing of coronavirus infections that are asymptomatic. If an infected individual does not show symptoms, they are not tested or counted in Rospotrebnadzor’s statistics unless they later seek medical help on their own.

How often COVID-19 is latent and whether it’s infectious if it does not cause symptoms are still open questions, but epidemiologists have issued estimated answers. For example, a group of scientists at Imperial College London analyzed air travel data from China to various countries, assuming that the proportion of infected passengers traveling from China was identical for each destination country. When the epidemiologists also assumed that countries like Singapore, which detected the highest infection rate among Chinese arrivals, had in fact detected every infection, they concluded that about two thirds of cross-border coronavirus cases have remained undetected.

There are flaws to this methodology, especially because the researchers used flight statistics from 2016 and did not take travel restrictions into account. However, the fact that Italy and Russia typically have similar air traffic flows from China does not bode well for Russia.

Hypothesis 4: Russia isn’t using the best available test for the virus

There are two kinds of tests that can point to the presence of the new coronavirus: tomography, which provides a description of clinical symptoms like pneumonia, and a laboratory test that determines whether the virus’s genetic material is present in a given sample from a patient. Lab tests can yield false negatives if the concentration of viral RNA in a sample is too low to be detected, but tomography can give rise to false positives because it detects a range of different respiratory illnesses.

In Russia, lab tests are being conducted using PCR (polymerase chain reaction) diagnostic panel kits produced by a Novosibirsk-based business called Vektor. However, the protocol for using that kit differs significantly from the testing systems in place in other countries, Meduza found. We obtained a copy of the Vektor-PCRrv-2019-nCoV-RG protocol and compared it to analogous methods from developers in the U.S., Germany, France, Japan, Thailand, and elsewhere.

While most countries are using single-stage tests that include a positive control (i.e., a sample of viral RNA that should always be detected if the test is functioning properly), Russia’s tests have two stages: Reverse transcription and PCR are conducted separately. The second stage uses Vektor’s kit, but whether that part of the test works depends on the first stage, which is entirely up to the laboratory conducting the test. The kit recommended for use in the first stage is called Reverta-L, but it is not specific to the new coronavirus, does not include a positive control, and cannot guarantee that a negative test result actually indicates an absence of the virus. We contacted Rospotrebnadzor for comment on this issue and did not receive a response within 24 hours.

Hypothesis 5: The number of coronavirus cases recorded in Russia is a vast underestimation, but most patients haven’t needed medical help

When we asked clinical infectious disease specialist Valentin Kovalev to comment on the situation surrounding coronavirus diagnoses, he expressed certainty that people infected with the new virus have in fact entered Russia. “I think the coronavirus infection got to us from China a long time ago, and a lot of people have already contracted it. However, we don’t know about those cases because most of the time, the infection feels just like any other ordinary respiratory illness, and people who are infected get better on their own. Nobody here is about to routinely check everyone who comes down with a cold at home.”

Kovalev pointed out that only laboratory testing can truly confirm the presence of the virus and that in asymptomatic cases, where individuals carry the virus without experiencing a fever or respiratory problems, only post-facto antibody testing typically does the trick. “Theoretically,” he said, “we could find every case if we carry out complete tests for everyone who has a cold. That’s not happening, but it wouldn’t make much sense, either.”

Meanwhile, evolutionary biologist Georgy Bazykin of the company Skoltekh gave Meduza a more positive but less certain prognosis. Bazykin said he “doesn’t have a good answer” as to why Russia has so far avoided a mass outbreak. “It’s possible that someone brought in [the virus] but got better without infecting anyone,” he speculated. “It’s possible that there are a lot of undetected cases — some data indicate that about two thirds of all cross-border transfers have not been detected — but I haven’t seen any direct evidence confirming that there are hidden cases in Russia,” he concluded.