There is an undiscovered immunity against SARS-CoV-2?
The Coronavirus pandemic is often compared to the swine flu H1N1 in 2009. At that time a serious global disease, it was predicted shaft with numerous deaths, which was then but much milder than expected. How did this gross miscalculation?
Professor Dr. Christian Drosten, Director of the Institute for Virology at the Charité hospital in Berlin, recently stated in the NDR Podcast “Coronavirus-Update”, how it came to be that the swine flu was predicted in 2009, initially as a deadly pandemic, but unexpectedly mild. Many people think that it could be the Coronavirus SARS-CoV-2 as well. In the case of the swine flu, other conditions were, however, entirely, such as the Coronavirus expert Drosten shows.
False alarm in the case of the swine flu
The swine flu in 2009 was much milder than the experts predicted. “Since patients are not turn passed away as a normal seasonal Influenza, but also not less, as it is shown sometimes,” says Drosten. Today, you will know exactly why you have miscalculated at that time. The swine flu was not completely harmless, however, there was at that time not known effects, with the result that the pandemic was so mild.
Old people were resistant to the swine flu
Then, animal experiments gave the impression that the H1N1 Virus could be much more dangerous for the people, as in the end of the day turned out. “And what you saw, but only after many months, was something that was surprising, and although one has not only seen changes in the incidence data that the Old in the population are not so seriously ill,” says Drosten. Just the people that you suspected as a risk group, showed a surprising resistance to the Virus.
Certain groups of the population had a background of immunity
Research to this observation then showed the reason: “You have seen that just those patients who had a certain age, had a background of immunity, both at the cellular level, as well as later on, measurable, more accurate Tests that you have carried out, even visible on the antibody level,” summarizes the virologist. Today, you know where this background immunity came.
How did this unexpected background immunity?
To explain how the unexpected immunity came to be, you have to go back to the Spanish flu in 1918. This pandemic Influenza was also caused by a H1N1 Virus. “This H1N1 Virus circulated until 1957,” says Drosten. Thereafter, the Virus was replaced by an H2N2 Virus, the so-called Asian flu, which killed up to 1968 have been prevalent and then, in turn, from the Hong Kong flu, H3N2, has been replaced. “This H3N2 Virus circulates up to today,” says the virologist.
In 1977 there was a further small pandemic a H1N1 Virus – the so-called Russian flu. “This H1N1 Virus is the same H1N1 Virus of the Spanish flu and its successor, which circulated between 1918 and 1947,” says the Virus expert. This Virus is circulated up to the year 2009.
H1N1 Virus-mediated cross protection
The Spanish flu and the Russian flu of swine flu is similar, and placed a cross-immunity in certain population groups. An effect comes to bear, the epidemiologists “original antigenic sin” (anti genetic original sin) call. Drosten explained that this effect States, that the Influenza, with the man infected First in life, is anchored to the strongest in the immune memory for the Rest of your life.
“We were looking back from the year of 2009, now two groups in the population who had an immunological memory against H1N1,” concludes the virologist. The most important group was the group that suffered its first Influenza-illness caused by the virus, the direct successor of the Spanish flu. All of those were in 2009, older than 51 years of age, had come, in all probability, already with the H1N1 Virus in contact, whereby it could immune memory to the swine flu effectively respond.
In addition, there was a group of younger patients and patients who came through the Russian flu, also H1N1 virus in contact. These complex relationships, which developed later, were underestimated, or were not known.
Could there be such a cross-immunity even in the case of corona virus?
Drosten stresses that you know currently exactly how it behaves with the cross protection in the case of the Coronavirus SARS-CoV-2. After all, there are also other, less dangerous, corona viruses that circulate during the flu season. Theoretically, it is possible that a certain degree of background immunity in SARS-CoV-2 is in some people. “There are new studies coming out these days, the present cross-protection data also suggests, there is a bit of cross-protection, but certainly not, I dare say now it’s time to, certainly not to the extent that it was, apparently, in the case of the 2009 H1N1 pandemic, the case,” says Professor Drosten. (vb)
Read also: Spanish flu pandemic – history, causes, and symptoms.