A group of 624 people have been investigated at Icahn Medical School on Mount Sinai after overcoming the flu virus. The preliminary results worried the researchers, as they only counted 511 immune cells and 72 people did not create antibodies. It should be noted that the people who were used for the research passed the virus mildly, of which only 3% were hospitalized.

However, the investigation was given a second chance and antibodies with memory were generated at the above 72 (memory antibodies occur when a second contact with the virus has occurred). Of this sample of 624, three were those who did not develop immunity. From the experiment it is concluded that the time of the serological test is very important, that it is better to do the test 24 days after passing the virus.

The finding is important in the race for the virus, as scientists know that the only way to overcome the virus is to develop immunity. It is still unknown whether this immunity can be provisional or final, but it has opened the way for further investigations.