Connect with us

Health

Covid: Why Omicron Is Less Severe – Studies Reveal One Strong Reason

Published

on

A spate of new studies on lab animals and human tissues are providing the first indication of why the omicron variant causes milder disease than previous versions of the coronavirus.

In studies on mice and hamsters, omicron produced less-damaging infections, often limited largely to the upper airway: the nose, throat and windpipe. The variant did much less harm to the lungs, where previous variants would often cause scarring and serious breathing difficulty.

“It’s fair to say that the idea of a disease that manifests itself primarily in the upper respiratory system is emerging,” said Roland Eils, a computational biologist at the Berlin Institute of Health, who has studied how coronaviruses infect the airway.

In November, when the first report on the omicron variant came out of South Africa, scientists could only guess at how it might behave differently from earlier forms of the virus. All they knew was that it had a distinctive and alarming combination of more than 50 genetic mutations.

Previous research had shown that some of these mutations enabled coronaviruses to grab onto cells more tightly. Others allowed the virus to evade antibodies, which serve as an early line of defense against infection. But how the new variant might behave inside of the body was a mystery.

“You can’t predict the behavior of virus from just the mutations,” said Ravindra Gupta, a virus expert at the University of Cambridge.

Over the past month, more than a dozen research groups, including Gupta’s, have been observing the new pathogen in the lab, infecting cells in petri dishes with omicron and spraying the virus into the noses of animals.

As they worked, omicron surged across the planet, readily infecting even people who were vaccinated or had recovered from infections.

But as cases skyrocketed, hospitalizations increased only modestly. Early studies of patients suggested that omicron was less likely to cause severe illness than other variants, especially in vaccinated people. Still, those findings came with a lot of caveats.

For one thing, the bulk of early omicron infections were in young people, who are less likely to get seriously ill with all versions of the virus. And many of those early cases were happening in people with some immunity from previous infections or vaccines. It was unclear whether omicron would also prove less severe in an unvaccinated older person, for example.

Experiments on animals can help clear up these ambiguities, because scientists can test omicron on identical animals living in identical conditions. More than a half-dozen experiments made public in recent days all pointed to the same conclusion: Omicron is milder than delta and other earlier versions of the virus.

On Wednesday, a large consortium of Japanese and American scientists released a report on hamsters and mice that had been infected with either omicron or one of several earlier variants. Those infected with omicron had less lung damage, lost less weight and were less likely to die, the study found.

Although the animals infected with omicron on average experienced much milder symptoms, the scientists were particularly struck by the results in Syrian hamsters, a species known to get severely ill with all previous versions of the virus.

“This was surprising, since every other variant has robustly infected these hamsters,” said Dr. Michael Diamond, a virus expert at Washington University and a co-author of the study.

Several other studies on mice and hamsters have reached the same conclusion. (Like most urgent omicron research, these studies have been posted online but have not yet been published in scientific journals.)

The reason that omicron is milder may be a matter of anatomy. Diamond and his colleagues found that the level of omicron in the noses of the hamsters was the same as in animals infected with an earlier form of the coronavirus. But omicron levels in the lungs were one-tenth or less of the level of other variants.

A similar finding came from researchers at the University of Hong Kong who studied bits of tissue taken from human airways during surgery. In 12 lung samples, the researchers found that omicron grew more slowly than delta and other variants did.

The researchers also infected tissue from the bronchi, the tubes in the upper chest that deliver air from the windpipe to the lungs. And inside of those bronchial cells, in the first two days after an infection, omicron grew faster than delta or the original coronavirus did.

These findings will have to be followed up with further studies, such as experiments with monkeys or examination of the airways of people infected with omicron. If the results hold up to scrutiny, they might explain why people infected with omicron seem less likely to be hospitalized than those with delta.

Coronavirus infections start in the nose or possibly the mouth and spread down the throat. Mild infections do not get much further than that. But when the coronavirus reaches the lungs, it can do serious damage.

Immune cells in the lungs can overreact, killing off not just infected cells but uninfected ones. They can produce runaway inflammation, scarring the lung’s delicate walls. What’s more, the viruses can escape from the damaged lungs into the bloodstream, triggering clots and ravaging other organs.

Gupta suspects that his team’s new data give a molecular explanation for why omicron does not fare so well in the lungs.

Many cells in the lung carry a protein called TMPRSS2 on their surface that can inadvertently help passing viruses gain entry to the cell. But Gupta’s team found that this protein does not grab on to omicron very well. As a result, omicron does a worse job of infecting cells in this manner than delta does. A team at the University of Glasgow independently came to the same conclusion.

Through an alternative route, coronaviruses can also slip into cells that do not make TMPRSS2. Higher in the airway, cells tend not to carry the protein, which might explain the evidence that omicron is found there more often than the lungs.

Gupta speculated that omicron evolved into an upper-airway specialist, thriving in the throat and nose. If that is true, the virus might have a better chance of getting expelled in tiny drops into the surrounding air and encountering new hosts.

“It’s all about what happens in the upper airway for it to transmit, right?” he said. “It’s not really what happens down below in the lungs, where the severe disease stuff happens. So you can understand why the virus has evolved in this way.”

While these studies clearly help explain why omicron causes milder disease, they do not yet answer why the variant is so good at spreading from one person to another. The United States logged more than 580,000 cases on Thursday alone, the majority of which are thought to be omicron.

“These studies address the question about what may happen in the lungs but don’t really address the question of transmissibility,” said Sara Cherry, a virus expert at the Perelman School of Medicine at the University of Pennsylvania.

Diamond said he wanted to wait for more studies to be carried out, especially in people instead of animals, before endorsing the hypothesis that TMPRSS2 is the key to understanding omicron. “I think it is still premature on this,” he said.

Scientists know that part of omicron’s contagiousness comes from its ability to evade antibodies, allowing it to easily get into cells of vaccinated people far more easily than other variants. But they suspect that omicron has some other biological advantages as well.

Last week, researchers reported that the variant carries a mutation that may weaken so-called innate immunity, a molecular alarm that rapidly activates our immune system at the first sign of an invasion in the nose. But it will take more experiments to see if this is indeed one of omicron’s secrets to success.

“It could be as simple as, this is a lot more virus in people’s saliva and nasal passages,” Cherry said. But there could be other explanations for its efficient spread: It could be more stable in the air or better infect new hosts. “I think it’s really an important question,” she said.

 

 

Health

COVID: Students, Teachers With High Temperature Should Be Sent Back Home – NCDC

Published

on

By

The Nigeria Centre for Disease Control (NCDC) says teachers and students with high temperature should not be allowed into schools.

In its latest COVID-19 situation report, the agency said the detection of the Omicron variant which has been found to be more transmissible, has intensified the need to ensure the implementation and adherence to public health measures against the virus.

It said COVID-19 and its variants spread easily when people come in close contact with one another, and therefore advised schools to take adequate precautions as they resume amid the fourth wave of the pandemic.

“School administrators should ensure the following to reduce the risk of COVID-19 transmission within schools: Daily temperature checks at points of entry. Those with a temperature above 38oC should not be allowed entry,” the report reads.

“Provision of handwashing facilities and hand sanitizers for hand hygiene. Masks must be worn by all those over the age of 6 years on school premises.

“Always ensure proper ventilation and minimum of one metre sitting distance between students in classrooms.

“Surfaces including desks, door handles etc. should be disinfected at least twice; at break time and at the end of the school day.

“Avoid sharing of items such as pencils, biros, erasers, rulers, textbooks. Staff at sick bay should be trained and provided with required Personal Protective Equipment (PPE).

“Students and staff who feel ill should remain at home and seek treatment at a health facility immediately.

“All eligible persons should get vaccinated against COVID-19 at one of the nearby vaccination sites.

“Those who are vaccinated must still adhere to public health measures.

“Additionally, NCDC recommends the use of approved rapid diagnostic test kits in secondary school hostels and university campuses for testing of student and staff upon school resumption and for those experiencing symptoms of COVID-19 during the school session.”

Since Nigeria’s index case in February 2021, a total of 248,732 confirmed cases, 219,479 recoveries, and 3,085 fatalities have been recorded in 36 states and the FCT.

Continue Reading

Health

FG Tells Govs To Enforce Compulsory Vaccination For LG, State Workers

Published

on

By

The National Primary Healthcare Development Agency (NPHCDA) has urged state governments to work towards mass vaccination against COVID-19 as part of moves to combat the virus.

The agency, in its latest advisory obtained by one of our correspondents in Abuja, also urged state governors to enact and enforce vaccination mandate for local and state government workers.

This came to fore as the percentage for fully vaccinated Nigerians stalled at 4.2 per cent while those that had taken their first dose remained grounded at 9.8 per cent as of Sunday, January 9, 2021.

The NCDC in its daily updates continued to report increase in the number of fatalities reporting no fewer than 38 deaths between January 1 and January 8.

Despite the increasing number of cases and deaths, some states have not vaccinated up to 200,000 individuals while Abia, Kogi and Niger states have not commenced administration of booster shots.

While some states had commenced the booster administration, analysis by our correspondent revealed that Akwa-Ibom, Anambra, Benue, Ebonyi, Imo, Kwara, Sokoto and Yobe had yet to administer boosters up to 100 residents.

While Imo had only administered ten booster shots, Ebonyi administered 52, Akwa Ibom administered 67 among others.

NPHCDA urges states to set up mass vaccination sites in markets, others

But the NPHCDA in its bid to speed up vaccination, in its advisory told governors that it was part of their responsibility to enact and to enforce vaccine mandate on state and local government workers.

The Secretary to the Government of the Federation, Boss Mustapha had in October announced that Federal Government workers who failed to show proofs of vaccination would be barred from government offices.

The Executive Director of the NPHCDA, Dr Faisal Shauib had another press briefing in 2021 had said that individuals who refused to get vaccinated would not be allowed to infect other people.

The Presidential Steering Committee went ahead to issue a vaccination mandate to Federal civil servants. The Boss Mustapha-led Committee had stated that Federal Civil servants without proof of vaccination and negative PCR tests would not be allowed into their respective offices as of December 1, 2021.

The federal civil servants who refused to adhere to the mandate were turned back home while others had to visit makeshift vaccination sites to get vaccinated.

State governments of Kaduna and Ondo states had also enforced vaccine mandate on state workers. But in a fresh advisory sighted by our correspondent, the NPHCDA advised governors to enact and enforce the same vaccination mandate on state and local government workers.

The advisory partly reads, “Enact and enforce vaccine mandate for all state and local government workers, direct mandatory set up of mass vaccination sites in public places including markets, parks, event centres, stadia and academic institutions.

“Approve and direct the release of state counterpart funds for advocacy, communication and social mobilization, logistics and additional teams in quarterly tranches.

“Pay weekly unscheduled visits to at least one mass vaccination site to supervise and motivate the vaccination teams, chair weekly review meetings with traditional and religious leaders to address vaccination gaps.

But the Senior Special Assistant to the FCT minister, Dr. Ejike Orji told one of our correspondents that the final decision to enforce the vaccine mandate lay on the minister.

He said, “Well the vaccine mandate is a Federal Government policy and it is expected that each state will start the process. A lot of people think we are trying to force it but what the government is saying is that if you have a right to not get vaccinated, other people also have rights to not getting the virus from you.”

“Sooner or later, the FCT will give the instruction. it is the mandate of the minister to do so and he will decide when to fully enforce it.”

In a related development, the Ekiti State Chief Judge, Justice John Adeyeye, has taken delivery of equipment to facilitate virtual court sittings, saying that he has issued a practice direction which includes among others use of appropriate technology for timely and effective disposal of cases.

The CJ, who spoke in Ado Ekiti while receiving laptops and printers from the state government for the commencement of virtual sessions in the courts, said that the new Practice Direction had been available for use by stakeholders in courts of the state since January 4.

Adeyeye said the objectives of the Practice Direction included “timely and efficient disposal of cases, use of suitable technology, just determination of proceedings, efficient use of available judicial and administrative resources among others.”

“Other aspects of the Practice Direction shall involve service of processes electronically, preparation for remote hearing, conduct of remote hearing, recording, adoption of written addresses, notice of delivery of judgments and rulings.

“The Practice Direction is pursuant to Section 274 of the Constitution of the Federal Republic of Nigeria, 1999 (as Amended), Order 45 of the High Court of Ekiti State (Civil Procedure) Rules 2020, Section 354 (1) of the Administration of Criminal Justice Law of Ekiti State, 2014 and any other enabling legislations,” he said.

Accordingly, the Practice Direction shall apply to cases involving urgent or time-bound Interlocutory applications, fundamental human rights, where the applicant is in custody and other matters as the chief judge may approve.

The State Attorney General and Commissioner for Justice, Wale Fapohunda (SAN), who presented the items to the CJ on behalf of the state government, said, “The equipment will serve as veritable tools in handling the virtual court sittings.”

 

Continue Reading

Health

States Reopen COVID-19 Isolation Centres As Cases Rise

Published

on

By

State governments have revived their various isolation centres in preparation for possible admission of COVID-19 cases, as the numbers continue to rise across the country.

Punch reports that officials of states including Ogun, Gombe, Benue, Lagos, Ondo and Sokoto, confirmed they had enough bed spaces to admit COVID-19 patients.

The number of officially confirmed COVID-19 infections hit 236, 014 as at Saturday, while the rate of full vaccination was stalled at 3.9 per cent.

Despite the increasing cases, the Nigeria Police Force, the military, and other security agencies have failed to enforce the compulsory vaccination mandate for their personnel.

On Friday, the country recorded 1,584 new cases, while on Saturday the Nigeria Centre for Disease Control confirmed 1,305 new cases of the virus.

The agency added that on Saturday alone, 21 persons died of COVID-19 complications bringing the fatality toll across the 36 states and the Federal Capital Territory to 3,014.

 

Continue Reading

Trending

%d bloggers like this: