Covid wave in China is a warning to Brazil and the world that the pandemic is not over

The explosion of new cases in China since the restriction measures known as “Covid zero” were withdrawn by the government raises concern for Brazil and the world.

According to experts, the scenario remains the same as seen in other waves of the pandemic: the high rate of transmission of the virus is the backdrop for the generation of more mutations and, with them, new potentially worrying variants.

The situation that is repeated is a warning that the pandemic has not yet come to an end, they reinforce.

As a result, countries such as the United States and the European Union have already announced that they will require a negative Covid test from all travelers from China starting in January.

For Flávio Fonseca, a virologist from UFMG (Federal University of Minas Gerais) and CT Vacinas (vaccine technology center, linked to the federal government of Minas Gerais), the risk of a new variant emerging in the Asian country with the possibility of spreading to the rest of the world is great.

“It is a real fear, because the conditions are certainly favorable for the emergence of a new variant”, he explains. “As the virus seeks to replicate itself, and it is through replication that new variants emerge, a more aggressive form may appear in a susceptible population, we still don’t know.”

In a country with low vaccination coverage and unclear official data on infections and deaths, it is difficult even to know the real dimension of the new wave.

Fernando Spilki, virologist coordinator of Rede Corona-ómica BR, linked to the Ministry of Science, Technology and Information, points out that the withdrawal of measures exposed a problem in terms of testing capacity, with some data indicating that the country may have up to 37 million of new infections per day and more than 5,000 daily deaths.

In official numbers, however, the Chinese government released less than 4,000 cases on the last day 22 and reduced the number of official deaths in the last week, from 5,242 to 5,241 dead. According to the World Health Organization, however, the country has already recorded at least 31,000 deaths since the beginning of the pandemic until the last November 29th.

“In population groups as large as China’s, it is very difficult to manage the population. Now, with the withdrawal [das medidas]we see that even for similar megalopolises the way the government followed the cases is very different”, he says.

The difference between the official numbers and those recorded by independent bodies is due to the recent change in the criteria for classifying a death from Covid in China, which only considers those related to respiratory problems directly associated with the virus.

According to the Chinese government, the change occurred because omicron is less aggressive in the lower respiratory tract (lungs and trachea), mainly causing an infection in the upper airways that can generate symptoms similar to those of the flu.

With regard to cases, China only accounts for positive results with RT-PCR tests, which look for the genetic material of the virus in the body, and many carry out antigen tests at home, which are not officially reported.

The vaccination coverage of the population is also an aggravating factor, with only two thirds of the elderly aged over 60 vaccinated with a booster dose. The vaccines used in China are mainly Coronavac, from the Chinese pharmaceutical Sinovac, and Sinopharm, both of which are inactivated viruses, which can generate less protection against infection.

“Now it’s around 67% of people vaccinated with a booster, albeit with two doses [esquema primário] exceed 89%, but they are vaccines with a lower degree of effectiveness, mainly for blocking variants, so it is a context that may be important for new global outbreaks”, says Spilki.

As a result, many Chinese are now traveling to Macau to receive immunizers from Pfizer or Moderna, using RNA technology.

“China invested in a policy of prolonged and intense lockdowns instead of high vaccination. This delayed, but did not prevent, the waves of Covid, which are now coming with great intensity and may reflect on the rest of the world”, says Fonseca.

For Raquel Stucchi, infectologist and researcher at Unicamp, the policy of using only inactivated virus vaccines ended up generating less immunity in the population. Several studies point out that heterologous vaccination or so-called vaccine mixture (as an RNA vaccine booster in those who received two doses of inactivated vaccines) generates a stronger and longer-lasting immune response.

According to her, the high number of cases may also lead to a shortage of medical supplies in the world. “We know that China is a pharmacological powerhouse, being the main producer of raw materials for medicines, vaccines and even tests, so if they need more for domestic consumption, they can restrict shipping to other countries,” she says.

Despite criticism of the Chinese Covid-zero planning, other specialists point out that the national strategy has made it possible to manage the pandemic even better in the last three years than in different parts of the world.

For Lorena Barberia, a political scientist and researcher at USP, the change in government management may even decentralize control measures, but there has not been a complete abandonment.

“It is important to contextualize that for three years they maintained a consistency in the way of tracing, isolating and testing contacts. The policy was very different from that of Western countries, and now, in a different epidemiological situation, they understood that the change in criteria was necessary”, says she, who also sees the media coverage of the Asian giant with a bias.

“In terms of population, the African continent has the same number of people, and there is not much transparency in the data from different countries, not to mention vaccine inequality. The concern about new variants emerging is true, but there is also very little knowledge about the way the pandemic continued there.”