These days, foreign press [1-3] often ask me the question above (why the blockade in HCMC doesn’t work), and I can only explain through 3 hypotheses related to time and context.
From any angle, the blockade policy of Ho Chi Minh City has not achieved its goal. The number of infections is still increasing and has not tended to decrease. Mortality rate increased beyond the mark (2 times) the average in the world. All the predictions were horribly wrong. The economy was severely affected, businesses left. More importantly, the scene of hungry people appeared. So, anyway, the blockade was unsuccessful.
1. Why is the blockade not effective?
Currently, no one has analyzed the problem properly because there is too little data. I think of two hypotheses: the duration of the blockade and the population characteristics of the City.
Fake The first theory is that the blockade measure was applied a bit late. When the blockade policy was enacted, the number of daily infections in Ho Chi Minh City reached 464 a day, a double increase compared to the previous ones. This means that the epidemic has ‘taken root’, and at that time the blockade has little effect.
Most of the model analysis that I read proves that if the blockade is applied immediately after the epidemic arises, it will be effective. Those analyzes also suggest that lockdowns should only be short, and that if prolonged, the effects will wear off over time (also known as ‘lockdown fatigue’).
The second hypothesis is the population characteristics in HCMC. We know that HCM has a fairly high population density, and a large part of the population lives in narrow alleys. A large part of residents have low income and they live on weekly or monthly salary. These are the ‘weakest’ groups of people, understood in the sense that they are susceptible to illness and suffer severe consequences when they get sick.
Experience of blockade in poor countries (such as Africa)  shows that in places where population density is high and sanitation is lacking, lockdowns are ineffective. The situation in South Africa is as expected: after several months of lockdown, the number of infections and deaths is still increasing. The strange thing is that after the blockade, the number of deaths seems to decrease.
The third hypothesis is the Delta variant. Surely this variant appeared in Vietnam. With a very high coefficient of transmission (6-7), and when the virus enters a family, there is a high probability that the whole family is infected. (Previously, only about a third of families were infected.) The Delta variant has a rather short incubation period, and this makes tracing or ‘quick testing’ very ineffective, as it has already spread to others before it is detected.
Therefore, I think the above three factors (time of lockdown and characteristics of residents) can explain why the blockade doesn’t work.
2. Blockade = selection
When we decide to blockade, we have made a choice. The choice is to save people infected with covid and (indirectly) sacrifice others with other diseases. These are chronic diseases such as diabetes, vascular injection, cancer, kidney, bone and joint diseases, immunity, etc.
We often talk about the number of more than 10,000 people who died in Ho Chi Minh City during this epidemic, but no one knows how many died due to covid and how many died WITH covid. I have reason to believe that most people die with covid.
Why do I believe that? Because looking at the number of deaths (see picture), I see 35% of all deaths are in people under 60 years old. Thirty-five percent. (Please note that in Australia, the number of deaths under 60 years old accounts for only about 1%.) The figure of 35% of many deaths under the age of 60 indicates that they are more likely to die from comorbidities than from the virus. During the blockade, we ‘sacrificed’ them.
3. What to do?
If it is determined that the blockade is not effective, then think about lifting the blockade policy. If according to WHO, the number of infections must be controlled (understood in the sense of a 14-day reduction), the health system is ready, etc. But is it necessary to follow WHO? I think not, because the standards they set are common to the world, and the application to each place depends on the conditions there. Besides, some WHO standards are outdated in the situation where there is a vaccine.
The new vaccine is the key to escape the blockade. The number of positive cases is not and should not be the criterion for exiting the blockade. In Ho Chi Minh City, the number of people over 18 years old receiving 1 dose is quite high (over 90%?) and the number of people receiving 2 doses is nearly 50% (?). I think that’s the standard to get out of the blockade. Exit following the 4-step route I outlined the other day .
Counting the cost of Vietnam’s Covid meltdown
Vietnam’s Ho Chi Minh City has highest COVID death rate in region
Vietnam vows to curb COVID in Ho Chi Minh City as deaths spike
 Some people are rightly concerned that if the blockade is stopped, the city will be “open”. I don’t like that vague word usage (what is ‘tang’?) I have to think more specifically than ‘tang’ in general. It is predictable that after exiting the blockade the number of cases may increase, but the number of hospitalizations will decrease. Imagine there are 10,000 positive cases, and of these, 1500 need to be hospitalized during the blockade, but after the vaccine, there are only 300 cases (due to the effectiveness of the vaccine reducing hospitalization by 80%). We can model like that for every day. However, to model properly, data on the number of hospitalizations during the lockdown is needed.