Cases of infection with COVID-19 have been reported even after completing vaccination against COVID-19. The US Centers for Disease Control and Prevention (CDC) is calling these cases “vaccine breakthrough cases” and calling for caution. What are the characteristics of this breakthrough infection?
The CDC defines a breakthrough infection as a case in which the COVID-19 virus SARS-CoV-2 RNA or antigen is detected in a respiratory sample of a person who has completed an FDA-cleared vaccination. In addition, the CDC defines the definition of complete vaccination in guidelines for people who have been vaccinated: one out of two vaccines developed by Pfizer or Moderna is more than two weeks after the second dose, and for Janssen vaccine two weeks after the first dose. It is stated that the time has elapsed.
The CDC said in the same guidelines that those who have been vaccinated will have a reduced risk of becoming infected with SARS-CoV-2 and dying. However, if breakthrough infection occurs only in a small percentage of cases and if infected with the highly contagious delta mutation, it is possible to infect other people, it is possible to wear a mask indoors in areas with a high infection rate for those who have completed the vaccination and to show symptoms of COVID-19. We recommend that you get tested.
According to the CDC, between January 1 and April 30, 2021, there were 1262 reported breakthrough infections in the United States. Of these, 2,725 were asymptomatic and 160 died. According to the CDC study, the median age of those infected was 58 and the median age of death was 82. In addition, from May 1 to July 19, 2021, 5,601 inpatients with breakthrough infection were reported in the United States, and 1,141 patients died. The CDC study found that patients who were hospitalized or died were older, immunodeficiency, or predisposed to pre-existing diseases.
According to one expert, breakthrough infection symptoms range from completely asymptomatic to severe and can lead to hospitalization or death. The CDC also explains that the chances of hospitalization or death are much lower than those who are not vaccinated.
While SARS-CoV-2 and other mutations are believed to transmit infection after 15 minutes of close contact, the delta mutation spreads rapidly, and delta mutation infection may be high between parents and children in close contact, although children under 11 years of age They are much less likely to become severe than adults.
According to a multi-country study published in November 2020, the basic reproduction number is between 2.4 and 3.4. The basal reproductive number is a number that shows how many people, on average, one infected person can develop in a completely immune-free population. According to statistics from the University of London research team, the effective reproduction number in the United States is 1.1 to 1.6 as of July 27, 2021. The effective reproductive number is an indicator that tells how many people on average one infected person generates per hour in a state where the mass infection is already spreading. On the other hand, the basic reproduction number of delta mutations is 5 to 9.5. For reference, the basic reproduction number of measles is 6-7, and the basic reproduction number of the 2009 influenza virus is 1.3-2.0. Related information can be found here.