- Carlos Serrano (@carliserrano)
- BBC News World
The rapid advance of the omicron variant of the coronavirus has health officials on high alert.
On Monday, the United States recorded a record 1.35 million new infections, the highest daily number of cases of any country, according to Reuters news agency data.
And on Wednesday, the Pan American Health Organization (PAHO) reported that, due to the omni, Covid-19 infections in the Americas have nearly doubled in the last week.
“Infections are accelerating in every corner of the Americas and, once again, our health systems are facing challenges,” warned Carissa Etienne, director of PAHO.
BBC News Mundo, the BBC’s Spanish-language news service, explains some aspects of the onomicron and why experts warn that the disease caused by this variant should not be considered mild.
1. Why is Omicron so contagious?
According to epidemiologist Maria Van Kerkhove, WHO’s technical lead for covid-19, there are three main reasons:
– This variant of the virus has developed mutations that allow it to more easily adhere to human cells;
– We have “immunity leak”. That is, people can be reinfected even if they have had the disease before or have been vaccinated;
– Omicron replicates in the upper respiratory tract, facilitating the spread of the virus, unlike delta and other variants that replicate primarily in the lower respiratory tract—that is, in the lungs.
The Covid Vaccine Hub indicates that it is difficult to estimate how transmissible the omicron is compared to other variants, but that some estimates from the UK Health Safety Agency suggest that it can be between two and more than three times more contagious than delta. .
The US Centers for Disease Control and Prevention (CDC) says that “it is likely” that the omicron spreads more easily than SARS-CoV-2, the original virus that causes covid-19, but that “not yet known” how easy it spreads compared to delta.
The CDC points out that anyone infected with a micron can spread the virus, even if they are vaccinated or have no symptoms.
2. What are the symptoms?
According to the Zoe Covid study, led by epidemiologist Tim Spector, from King’s College London, UK, so far it is known that the most common symptoms of the omicron variant are:
– Fatigue (mild or severe);
Even though, for some, covid may seem like “a bad cold”, the British public health service (NHS) indicates that we must remain attentive to the classic symptoms of covid:
– Sudden and continuous cough;
– Fever or high temperature;
– Loss or change in smell and taste.
3. Does the omicron cause less severe disease than the delta variant?
The CDC indicates that more data is needed to know whether the omicron infection causes a less severe or fatal disease compared to other variants.
Some indicators, however, suggest that in certain cases the omni may cause milder symptoms, but can still lead to hospitalization and death, especially in people who are not vaccinated.
On December 31st, the UK Health Safety Agency released a report showing that people infected with omicron were a third as likely to end up hospitalized compared to those infected with delta.
On the website of the Department of Public Health Sciences at the University of California at Davis, epidemiologist Lorena García notes that omicron symptoms can be very different between vaccinated and unvaccinated people.
“In those who are fully vaccinated and with booster doses, the symptoms tend to be mild. On the other hand, if the person is not vaccinated, the symptoms can be quite severe and lead to hospitalization or even death”, says Garcia.
The WHO warned, in turn, that the omicron should not be seen as a mild disease.
“While the omicron appears to be less severe compared to the delta, especially among those vaccinated, this does not mean that it should be classified as mild,” warned Tedros Adhanom Ghebreyesus, director of the WHO, in early January.
“Like the previous variants, the omicron is hospitalizing and killing people.”
4. Do vaccines work against the micron?
People with two doses of the immunizer remain protected from hospitalization, even if they have lost some protection against infection, according to Ignacio López-Goñi, a professor of microbiology at the University of Navarra in Spain, in an article published Dec. academic news site The Conversation.
A study by the Massachusetts Institute of Technology (MIT) and Harvard University, in the US, published on January 7, indicates that two doses of the Pfizer or Moderna vaccine “do not produce antibodies capable of recognizing and neutralizing the omicron variant”, but that “a booster dose dramatically improves protection” against it.
Andrew Lee, professor of public health at the University of Sheffield, UK, says the data show that two doses of Pfizer or AstraZeneca offer limited protection against the micron, but that protection is quickly restored with a booster dose, he explains. in an article published on The Conversation website on January 5th.
Lee also points out that it’s normal for some immunized people to get omicron, as vaccines are not designed to prevent infection, but to reduce the chances that someone who has been infected will develop a severe form of the disease or die.
“So far, vaccines have proven to be very good at preventing serious disease,” says Lee.
The CDC notes that “the emergence of the omicron emphasizes the importance of getting vaccinated and getting a booster dose.”
On 11 January, a WHO panel indicated that it is possible that vaccines against covid-19 need to be updated to ensure they are effective against new variants such as the omicron.
5. If I already had covid or am vaccinated, can I get Ômicron?
A report from the University of Imperial College London, UK, dated December 17, which is still under review, shows that the omicron has a great ability to evade immunity acquired from a previous infection.
The document estimates that the risk of reinfection with omicron is 5.4 times greater than with delta.
The protection against micron reinfection provided by a past infection can be as low as 19%, the study suggests.
Regarding vaccines, Dr. Gregory Poland, director of the Vaccine Research Group at the Mayo Clinic, USA, indicates that the protection they offer against the micron decreases over time.
“If you take two doses of the vaccine, after at least three months your protection against infection or hospitalization drops to about 30% to 40%,” Poland says on the Mayo Clinic website.
According to him, with the booster dose, immunity can reach between 75% and 80%.
“Notice I didn’t say 100%,” warns Poland.
“That’s why we still wear a mask. That’s why we still maintain distance.”
“What we knew from the previous variants is that people with hybrid immunity (vaccine + infection) developed a more potent and lasting immune response than those who were only vaccinated or only infected”, says Salvador Peiró, a specialist in public health and a researcher in pharmacoepidemiology. at FISABIO, a biomedical research foundation in Spain.
Peiró warns, however, that the ômicron has managed to infect people who have already had the disease or who have already been vaccinated, at least after some time (more than five or six months) since vaccination or infection.
“In theory, yes, although reinfections are extremely rare in the following months after overcoming covid”, says Peiró.
He adds that these reinfections will be even rarer in people who, in addition to having overcome covid, have taken a third dose of the vaccine.
The specialist indicates that, due to how recent the infections are, it is not yet known for how long and to what extent these reinfections will occur.
Have you watched our new videos on YouTube? Subscribe to our channel!