Jakarta, CNN Indonesia –
Vaccine is said to be the only best way out of the pandemic corona virus Covid-19. Currently, there are more than 200 vaccines under development worldwide, about 20 of which are currently in the clinical trial phase.
Before vaccines were released, a number of parties had also conducted early-stage safety studies on animals and humans. In fact, several research teams conducted challenge trials in which animals given the vaccine candidate were deliberately exposed to SARS-CoV-2 to see if the punctures could prevent infection.
Launch NatureStudies in macaques show that vaccines do a good job of preventing lung infections and pneumonia, but don’t block infections elsewhere in the body, such as the nose.
Monkeys that received a vaccine made at the University of Oxford, UK, and then caught the virus had levels of viral genetic material in the nose comparable to levels in vaccinated animals.
Meanwhile, data in humans shows that the Covid-19 vaccine encourages the body to create strong neutralizing antibodies that can block the virus from infecting cells. However, it is unclear whether the antibody levels are high enough to stop new infections and how long the molecules remain in the body.
Scientists predict the vaccine will take a long time to create. University of Wisconsin virologist Dave O’Connor says a vaccine that works for people will be available in 12 to 18 months.
Nature of Immunity and Long Lasting Vaccines
Immunologists have been working quickly to determine what immunity to SARS-CoV-2 looks like and how long it can last. Most of the effort has focused on ‘neutralizing antibodies’ which bind to viral proteins and directly prevent infection.
Research has found that levels of neutralizing antibodies to SARS-CoV-2 remain high for several weeks after infection, but then begin to decrease.
However, the antibodies may stay at high levels longer in people who have very severe infections.
“The more viruses, the more antibodies, and the longer they last,” says immunologist George Kassiotis.
A similar pattern is seen in other viral infections, including SARS (severe acute respiratory syndrome). Most people who have SARS lose neutralizing antibodies after the first few years. Interestingly, those in severe condition still had antibodies when retested 12 years later.
Researchers do not yet know what levels of neutralizing antibodies are needed to fight reinfection with SARS-CoV-2 or at least to reduce Covid-19 symptoms. Thus, it is possible that other antibodies are important for immunity.
Virologist Andrés Finzi from the University of Montreal, for example, plans to study the role of antibodies in binding to infected cells and marking them for execution by immune cells, a process called antibody-dependent cellular cytotoxicity.
Because there are no clear and measurable markers in the body that correlate with long-term immunity, researchers must collect various immune responses and compare them with responses to infection with other viruses to estimate how long-lasting the protection will be.
Studies of other coronaviruses show that it ‘sterilizes immunity’, preventing infection may only last for a few months. However, immunity that can prevent or relieve symptoms is claimed to last much longer than that.
The effectiveness of the Corona Vaccine is only 50 percent
An allergy and infectious disease expert from the United States, Anthony Fauci, said that the efforts of scientists to create a Covid-19 vaccine that could effectively provide protection up to 100 percent was impossible.
“Scientists predict that the corona virus vaccine that will be produced can be at least 75 percent effective against the virus. Or at least 50 to 60 percent is safe enough,” said Fauci. BGR.
Speaking virtually through a webinar organized by the Brown University School of Public Health, Fauci then emphasized the importance of public awareness in controlling the pandemic rather than expecting a lot of vaccines.
The reason is, according to him the vaccine serves to control the corona pandemic better and is no bigger, does not mean eliminating 100 percent.
“So vaccines whose effectiveness level is below 50 percent can be approved by the US Food and Drug Administration (FDA),” Fauci said.
Previously, FDA Commissioner Stephen Hahn said he would certify the corona virus vaccine as long as it was safe and at least 50 percent effective against the virus.
Hahn also admitted that the US and other countries were most likely to get a vaccine capable of fighting the virus by 50 percent.
“Most of the infectious disease experts also agree that it is a vaccine with an effectiveness level of 50 percent that makes the most sense. Of course we hope it can be higher,” said Hahn.
According to the Centers for Disease Control and Prevention, a vaccine that is 50 percent effective will be roughly the equivalent of the influenza vaccine, but below the effectiveness of a single dose of measles vaccination, which is about 93 percent effective.
(jps / DAL)
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