The Delta strain spread and the epidemic situation picked up again. Recently, the number of confirmed cases of COVID-19 around the world has bottomed out and rebounded again. From a regional point of view, the epidemic situation in Europe is not optimistic, while the epidemic situation in the Americas is relatively moderate.

In the process of the rise of the global epidemic, the spread of Delta mutants has played a role that can not be ignored. According to the World Health Organization, as of July 20, Delta mutants have appeared in more than 120 economies around the world. The spread rate of Delta mutant is really astonishing.

In terms of the distribution of genetically sequenced cases in the world's major economies, Delta mutants accounted for less than 5 per cent of cases at the end of April, up from more than 95 per cent at the beginning of July. The rapid spread rate of Delta variant strains depends on its short incubation period, rapid transmission and strong pathogenicity. The transmission coefficient of Delta variant strains is significantly higher than that of general strains and Alpha variants.

The vaccine still has protective effect, and the effect of complete vaccination is better. In terms of the types of COVID-19 vaccines vaccinated in developed economies, Pfizer vaccines occupy the mainstream, while AstraZeneca and Modena also account for a certain proportion. According to the latest study based on British cases published in the New England Journal of Medicine (NEJM), after one injection, the protective effect of the existing vaccine against the Delta mutant is not as good as that of the Alpha variant, but after two injections, the protective effect of the vaccine against the two mutants is not significant.

For example, after complete inoculation with Pfizer, the effective protection rate for Alpha mutant strains can reach 93.7%, and the effective protection rate for Delta mutant strains can also be close to 90%. In the protective effect against severe diseases, most vaccines showed that the gap between Delta mutant strain and Alpha mutant strain was further narrowed.

According to data from a Canadian case-based study published on medRxiv, the effective protection rates of Pfizer, Modena and AstraZeneca against hospitalization and even death caused by Delta mutants are all more than 75 per cent. The UK-based case study, published on PHE, has similar conclusions.

Prevention, control and vaccination still need to be increased, and the trend of economic recovery remains unchanged. As far as the United States is concerned, the main problem facing the United States is that the speed of vaccination has declined, and the increase of vaccine coverage has encountered a bottleneck, which has a lot to do with people's willingness to vaccine. the proportion of unvaccinated and unwilling COVID-19 vaccination in the United States has been maintained at about 28%, and it is this group of people who have hindered the increase of vaccination coverage in the United States. Under the blessing of strong transmissibility of Delta mutant strain, the probability of infection of COVID-19 in the population that did not complete vaccination was increased.

For Europe, the main problem is the lack of epidemic prevention and control measures. Once the epidemic shows signs of being initially brought under control, European economies tend to relax control of the epidemic ahead of time, such as the release of the British blockade of England as scheduled.

Despite the resurgence of outbreaks in some economies and a sharp rise in the number of new confirmed cases, the rise in deaths in advanced economies is not fast, or means that the epidemic is not as severe as it was at the beginning of the year.

On the whole, although Europe, the United States and other developed economies have more or less problems in epidemic prevention and control, on the one hand, vaccines still have a protective effect on Delta mutant strains, and countries are also promoting the process of vaccination; on the other hand, this round of epidemic has not brought a significant increase in deaths.

Therefore, although the rise of the epidemic caused by Delta mutant strains interferes with the process of economic recovery to a certain extent, it will not interrupt the trend of economic recovery in developed countries.

Although the constraints of the epidemic on the economy are relatively limited, we do not have to expect too much from the subsequent overseas economic growth. We expect that the US economic growth will stabilize after reaching its pre-epidemic level of 2 per cent and 3 per cent, and the Chinese and US economies will "grow at a peak".