Covid-19: What Does A Booster Shot Do, Will It Knock Down Omicron?

Boosters appear effective. And while there's still no consensus among experts as to when, for whom, and for which vaccines a booster dose is needed at present, several countries have already gone ahead and rolled out booster shots to certain categories of their population.

One reason most often cited by experts for getting a booster shot: declining antibody concentrations, measured via "titre" tests. Here's a lowdown on COVID-19 booster shots:

What does a booster do? Why should I have it?

In a nusthell, a booster shot helps "remind" the body's immune system about the virus it needs to defend against. This improves or gives the immune system a "boost".

In general, protection from vaccines "wane" over time, experts say. A tetanus booster, for example, is recommended every 10 years. On the other hand, a study published in the journal Nature recently shows compelling evidence that the risk of severe COVID drops by factor of 20 in "high-risk" older adults who received a "booster" shot.

factor of risk reduction of severe COVID among adults given a booster shot, in one study.

Who should have the booster shots?

The study shows that Israelis above age 60 who received a third dose of a COVID-19 vaccine are much less likely to test positive for SARS-CoV-2 or to develop severe COVID-19 than those who have had only two jabs, according to the study published on September 15, 2021. Israel was the first country to widely adopt the booster. The booster drive has been credited in part for ending Israel's fourth wave. Several countries have also authorised booster shots for their citizens.

Is Omicron covered by booster shots?

Booster vaccines are not variant-specific at this point. In general, they can generate an immune response from the body against most known SARS-CoV-2 variants of concern. Some of the shots can be tailored to target new strains. Booster doses that offer protection against the Delta variant are still in trials.

That makes the race against variants tricky. Newer ones emerge with increasing regularity. Newer versions of a vaccine have to be designed, tested and approved before being shipped for inoculation. So it’s challenging to keep pace with new strains.

Omicron is a new strain. So none of the booster shots targets the latest strain. But a fully vaccinated person is better equipped to deal with Omicron or any other variant. All vaccines are effective in reducing the severity of COVID-19 infection, averting hospitalisation and preventing death. So booster jabs should work against Omicron, even at reduced efficacy.

Pfizer-BioNTech and Moderna have announced that they are working on boosters that will provide immunity against Omicron. Pfizer expects to ship them in 100 days.

Moderna CEO Stephan Bancel told the Financial Times on Tuesday: "There is no world, I think, where [the effectiveness] is the same level...we had with [the] Delta [variant]. I think it's going to be a material drop. I just don't know how much because we need to wait for the data. But all the scientists I've talked to ... are like, 'This is not going to be good'."

Much remains unknown about the Omicron variant, though scientists are racing to establish its severity, transmissibility and whether it "escapes" current vaccines.

What countries have authorised COVID booster shots today?

On Sunday (November 28, 2021), the UAE approved a COVID-19 vaccine booster dose for all fully-vaccinated adults aged 18 and above, 6 months after the second dose. The eligible categories include those who are fully vaccinated with the two doses of the Pfizer-BioNTech and Sputnik vaccine.

Following are the countries that deployed COVID-19 booster shots so far:

US
UAE
Saudi Arabia
Kuwait
Oman
Bahrain
Qatar
China
Israel
Canada
Brazil
UK
European Union
Philippines
South Korea
South Africa
Japan

We're updating this list as information becomes available.

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Is it possible to fight COVID without booster shots?

With evidence showing that the immunity levels wane 5-6 months after initial dosing, and continue to fall considerably post that, most immuno-compromised individuals may require prompt administration of these booster shots. As we have already seen, numerous countries have decided to fast-track the administration of booster shots, on top of full vaccination.

What factors must be considered in boosting defences against COVID?

Given the known anti-coronavirus tools available (intramuscular vaccines, COVID pills, upcoming intranasal shots), there are two key factors to consider: the threshold of antibodies in the general population and long-term protection.

New data show these may only be conferred through booster vaccinations at this point. Scientists now believe that given the efficacy decline in existing shots, repeat shots — or upgraded doses — would offer a much stronger defence against the virus and ensure the vulnerable population are immune-protected.

What’s the level of efficacy decline of existing shots?

A US Centers for Disease Control Prevention (CDC) case-control analysis of the mRNA-1273 vaccine showed a decline in efficacy from 93% to 92% — after 120 days from the completion of vaccination, in contrast to a decline from 91% to 77% for BNT162b2, the Lancet reported.

The journal also quoted a Kaiser Permanents population report which indicates that the effectiveness of the BNT162b2 (Pfizer) vaccine against the Delta (B.1.617.2) variant fell to 53% — 4 months after the second dose. However, effectiveness against admission to hospitals remained high at 93% up to 6 months. Other reports from Israel and Qatar indicate declining protection.

Should existing vaccines be tweaked? Do existing vaccines still work against the new known variants such as Omicron?

Although these reports strengthen the case for a booster dose of BNT162b2, there is no evidence yet to suggest breakthrough infections by Omicron variant leads to more severe cases. Global policies related to vaccines would certainly be influenced by the data given the new variant.

Health officials and experts have been monitoring the real-world performance of the COVID-19 vaccines to see how long protection lasts among vaccinated people, including the new variants. The mRNA vaccines continue to offer very strong protection against severe disease and death.

Dr Angelique Coetze, chair of the South African Medical Association, and one of their experts who discovered the Omicron variant, said: "Looking at the mildness of the symptoms, there is no reason for panicking, as we don't see severely ill patients".

South Africa has more than 35 per cent of the country already vaccinated, according to South Africa's Department of Health. It is way better off than many of the countries, where many have not reached a 2 per cent full vaccination rate for their citizens.

Coetze, while citing the "mild" and asymptomatic cases, caution that the situation "might change, going forward."

South African Doctor:

"Looking at the the mildness of the symptoms, there is no reason for panicking, as we don't see severely ill patients"

"The hype that's been created out there in the media & worldwide doesn't correlate with the clinical picture" pic.twitter.com/g7tSas0qqK

PROTOCOL IN MIDDLE EAST COUNTRIES ON BOOSTER SHOTS

Several countries in the Middle East have rolled out booster shots. The UAE and Israel are leaders in COVID-19 vaccination, and they have been among the first countries to offer vaccine boosters to residents. All Gulf countries have followed suit.
• UAE
The UAE was among the first countries to offer vaccine boosters. In May, third doses of Sinopharm were given to seniors and people with chronic illnesses. Earlier, a third dose was offered to people whose bodies did not create enough antibodies after vaccination. On Tuesday, booster shots of Pfizer-BioNTech and Sputnik vaccines were approved for UAE residents above the age of 18. A booster dose can be taken six months after the second dose.
Earlier, the dose was available only for people aged 60 and above, and those aged 50-59 with chronic diseases. The designated category also included patients in a long-term care setting if they are aged 18 or above.

• SAUDI ARABIA
Saudi Arabia has opened registration for booster shots for people over the age of 18 and those who got the second dose of the COVID vaccine at least six months. It had already started giving booster shots to the vulnerable categories, including renal failure patients, health workers, the elderly and people suffering from chronic diseases.

• BAHRAIN
In May, Bahrain made available booster shots of Sinopharm to first responders, residents older than 50 and people with underlying health conditions.

• OMAN
Pfizer booster doses are being administered to two sections. One group includes people aged 65 and above and frontline workers. People above the age of 18 who suffer from chronic diseases and such conditions are part of this group. The second group comprises immunocompromised people aged 12 and up. That includes patients undergoing cancer treatment, people who have undergone bone marrow and organ transplants, HIV positive people, and people on immune suppressants. Recipients must have completed at least eight months after receiving the last jab.

• KUWAIT
Kuwait has approved the rollout of booster doses in September. The country’s health services offer booster shots to people who have obtained the second dose of vaccination six months ago. The third jabs will be given to those above 60 years with underlying health conditions, frontline workers, and immunocompromised people.

• QATAR
Qatar announced on Sunday that all individuals who received the second vaccine dose at least six months ago are now eligible for a booster shot. In September, the country approved a booster dose of Pfizer and Moderna vaccines to people with weak immune systems and high-risk individuals who had their second dose of the vaccine more than eight months ago. High-risk individuals include people over 50 years of age, those who are immunocompromised, people with chronic medical conditions and frontline healthcare workers.

• ISRAEL
Israel was one of the first countries to offer the booster of the Pfizer vaccine. In July, the country began to vaccinate severely immunocompromised residents and people aged over 60. When the Delta variant rocked the country a month later, Israel provided booster shots to all citizens over 12 years. By now, nearly 50 per cent of Israel’s population has received a booster shot.

What do experts say about Omicron's transmissibility and ‘immune escape’ ability?

It's still too early to say, according to experts. What's clear now is that the variant is highly transmissible, with cases and hospitalisations rising six times already, though death is a lagging indicator. They also said the symptoms are different from Delta.

The thesis that "Omicron is mild" is driven by best hopes, not science. It has no basis in clinical data and peer-reviewed studies. It's more of a conjecture, or hope, instead of scientific fact backed by extensive clinical analysis.

Currently, there's no information to suggest symptoms associated with Omicron are severe, though initial infections reported were among university students — younger individuals who tend to have more mild disease.

On Monday (November 29, 2021), the WHO stated that the newly discovered variant is likely to spread internationally, thus posing a "very high" global risk where COVID-19 surges could have "severe consequences" in some areas.

Here's the latest list of countries where Omicron cases have been detected.

The UN agency, in technical advice to its 194 member states, urged them to accelerate vaccination of high-priority groups and to "ensure mitigation plans are in place" to maintain essential health services.

Further research is needed to better understand Omicron's potential to "escape protection" against immunity induced by vaccines and previous infections, the health body said, adding that more data was expected.

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Experts cite that understanding the level of severity of Omicron will take days to several weeks. All variants of COVID-19, including the Delta variant that is dominant worldwide, can cause severe disease or death, in particular for the most vulnerable people.

 

 

 

SOURCE  GULFNEWS

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