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More and more countries lift coronavirus restrictions, in particular on tourist entry. The Insider spoke with experts on whether the pandemic was defeated by vaccination and the collective immunity achieved, or whether it is still too early to draw conclusions.
Vietnam, Austria, Turkey, Cyprus and Italy no longer require vaccination certificates or COVID-19 tests from foreigners. In Spain, tourists will only need a test. In Shanghai, China, the lockdown imposed for more than two months has been lifted. Since June 14, Russia has also lifted the epidemiological restrictions on entry of foreigners. Meanwhile, in the United States, doctors again recorded an abrupt surge in infections, and virologists say the official statistics greatly understates the reality due to the use of home tests.
Statistics understates the reality due to home testing
Globally, the coronavirus isn't going anywhere: the numbers of infections, hospitalizations and deaths in the U.S., Taiwan and other countries are increasing, Ilya Yasny, head of scientific expert review at the pharmaceutical venture fund Inbio Ventures, told The Insider. He notes that it is becoming increasingly difficult to judge the situation by the number of infections, because in many cases people test themselves and do not report positive results. According to him, the official statistics on the infection rate in the U.S. probably understates the reality.
According to the epidemiologist Mikhail Favorov who heads the medical research company DiaPrep System Inc, the virus continues to circulate, and a real reduction in the incidence rate can only be recorded during the active season of respiratory infections, that is, in late September with a peak in November-December.
“For now, the threat to the human population has receded, but we'll see how the human population interaction will interact with the virus during the season,” the expert says, noting that the elderly, unvaccinated or non-boosted people will be at risk.
The situation could become unpredictable, coronavirus is evolving
According to Yasny, the coronavirus situation continues to be unstable. Different dynamics of the disease in different countries and the huge number of unvaccinated people in the poorest countries may cause the emergence of new coronavirus variants, which will make the situation less predictable, the expert stressed.
“The virus is actively evolving. We are not in a steady situation, as with influenza, which has existed alongside humanity for hundreds of years, but in a very dynamic and even chaotic one, because different countries have different variants that evolve differently, people continue to be vaccinated, although at a slow pace. It will probably be a few years before the situation stabilizes and we can make more reliable predictions. Every month tiny differences appear in the coronavirus genome, though not as fast as in the case of the flu; but still it is evolving,” the expert says.
Why restrictions are being lifted
The pandemic has taken a heavy toll on the global economy, but the decision to lift restrictions is not just because travel bans are hurting the economy, but because the authorities and health officials have decided to take more localized measures. Since the infection rate in Europe is low, and there are a lot of vaccinated people, the risks of opening the borders were considered to be lower. If hospitalizations suddenly increase sharply somewhere, those restrictions will be re-imposed, Ilya Yasny says.
“That is exactly what the next step should be in the fight against the pandemic, when it transforms from a global threat into a local one that can be dealt with locally. That was the plan from the beginning - close everything off, vaccinate everyone, and then open up and see what happens. It's very important to keep testing people, it's important to keep studying the coronavirus genomes to see how it evolves. All that is being done in Western countries. Things are worse in the U.S., but they have a well-developed practice of wastewater testing. And it is an infallible way of predicting real cases, because when people run tests at home and don't tell anyone anything, they still do go to the toilet, and you can find scraps of coronavirus genomes in the sewage,” the expert says.
The promised collective immunity may never be achieved
Globally, says Ilya Yasny, about 30% of the world's population has been vaccinated. The pandemic is not yet defeated by vaccination and collective immunity. In the U.S. and China, over 90% of the population has been vaccinated, but with local vaccines that are less effective than Pfizer and Moderna. In the U.S., many people are vaccinated, but vaccines lose their effectiveness rather quickly against the latest Omicron variants. A fresh booster is effective, but reinfection is possible, albeit in a mild form. People had an oversimplified idea of what collective immunity was, believing that a 60-70% vaccination rate was enough to create it, the expert says. According to Yasny, that is a very rough estimate. Different countries have different patterns of human communication, different population densities and mobility patterns, and it greatly affects the level of vaccination and morbidity at which collective immunity can be achieved.
If we take well-studied infections of the past and present, collective immunity for measles is achieved when more than 92-98% of the population is vaccinated. As soon as this percentage drops, a local outbreak starts. It has been seen in the United States and in some regions of Ukraine, where parents stopped vaccinating their children against measles. It was enough to reduce the number of vaccinated people by 3% for measles to start infecting people again. At the same time, after a single illness, measles develops lifelong immunity, the same immunity is afforded by vaccination, Yasny explains. The situation with coronavirus is different, because both vaccinated and over-vaccinated people can get sick again. There are models and expert opinions suggesting that with coronavirus collective immunity cannot be achieved at all.
According to Mikhail Favorov, the best way to develop sustainable immunity is to get a booster shot of a different vaccine.
“If you’ve got a dose of adenovirus vaccine (“Sputnik”) in Russia, the adenovirus vaccine booster is ineffective. If possible, it is better to be vaccinated again with an RNA vaccine such as Moderna or Pfizer. That way, you will have a different protein and the response will be one where the antibodies are different. Accordingly, if you were vaccinated with Pfizer or Moderna, it is better to get a Johnson & Johnson or a Sputnik in September. The most important goal of repeated vaccination is to get the most diverse type of antibodies, so a combination of vaccines seems to be the best strategy in this regard,” the epidemiologist says.
In turn, Ilya Yasny notes that the use of different vaccines has not been well studied: “If there is an opportunity to get a dose of the Pfizer vaccine, you should choose it by all means, as there are fewer risks, and when combined with other vaccines, it gives a reliable effect. If a person has been vaccinated with any other vaccine, and there is an opportunity to get a second shot of the Pfizer vaccine, it is also better to do it. As regards Russian vaccines, there are no alternatives to Sputnik, because all other vaccines have not proven their effectiveness and safety. Only Sputnik and nothing else.
Anna Titova