NEJM: 40% low viral load, mild symptoms and quick recovery, the new crown vaccine reduces the impact of infection

Although it is difficult to prevent infection 100%, the new crown vaccine helps to reduce the symptoms of new crown virus disease (COVID-19), which has been tested in clinical trials, but there are not many real-world data on this

This paper summarizes and analyzes the data of two prospective cohort studies supported by the US Centers for Disease Control and Prevention, covering a total of 3975 health care workers (53%), first responders (21%), and other basic staff in 8 locations in the United States.

During the period from December 14, 2020 to April 10, 2021, these subjects will be required to undergo nucleic acid testing via nasal swabs every week, regardless of whether they have symptoms or not; in the event of COVID-19-related symptoms, additional information will be required Nasal swabs and saliva samples

As of April 10, a total of 3179 people (80%) had received at least one dose of the approved mRNA vaccine, of which 2686 people (84%) had received two doses

During the study period, a total of 204 (5%) subjects were detected with new crown infection, of which 5 were fully vaccinated (≥14 days after the second dose), and 11 were partially vaccinated (≥14 days after the first dose, the first <14 days after 2 doses), 156 people were not vaccinated; 32 people received less than 14 days of the first dose of vaccination, which was regarded as an uncertain vaccination status and was not included in the analysis

After adjusting different vaccines, locations, occupations, and local virus transmission, the data shows that the effective rate of two doses of mRNA new crown vaccine is 91% for preventing infection, and the effective rate for partial vaccination against infection is 81%

Compared with unvaccinated infected individuals, those infected after partial or full mRNA vaccination have a 40% lower viral RNA load in their bodies

People who are vaccinated have shorter infection time, and the risk of nucleic acid positive for more than a week is reduced by 66%

The protective effect of the vaccine is also directly reflected in the milder condition and shorter course of the disease

The paper pointed out that in people with breakthrough infections, mRNA vaccines seem to reduce infections and alleviate diseases in a variety of ways

The research team said that the study also has certain limitations, such as a short follow-up time; it cannot be ruled out that the reduced viral load after vaccination has caused some infected people to actually not be detected; because the number of breakthrough infections is relatively small, it is impossible to distinguish between complete vaccination and complete vaccination.

In the future, if further data confirm that mRNA vaccination can reduce the viral load and duration of infection, thereby reducing the infectivity of the new coronavirus, it will show that the vaccine not only prevents infection, but also reduces the impact of breakthrough infection

Note: The original text has been deleted

Reference

[1] Mark G.

[2] COVID-19 vaccine reduces severity, length, viral load for those who still get infected.