What’s the best Covid vaccine? Why it’s not so simple: Quick take on seven issues

‘A range of vaccines with different efficacy results now has given rise to worries that some people may refuse the shot on offer in hopes of getting a “better” one later. In reality, comparing efficacy numbers isn’t necessarily the best way to measure a vaccine’s value. And as suppliers struggle to meet global demand, experts say the best vaccine for you is probably whichever one you can get now.’

Bloomberg's Quick Take answers seven questions:

1. What does efficacy mean?
2. What efficacies are being reported?
3. Are the numbers reliable?
4. Why isn’t efficacy all that counts?
5. So numbers may be misleading?
6. What matters beyond the efficacy number?
7. What’s the bottom line?

Read here (Bloomberg, Mar 15, 2021)

The differences between the vaccines matter

‘It’s certainly true that all three of the FDA-authorized vaccines are very good—amazing, even—at protecting people’s health. No one should refrain from seeking vaccination on the theory that any might be second-rate. But it’s also true that the COVID-19 vaccines aren’t all the same: Some are more effective than others at preventing illness, for example; some cause fewer adverse reactions; some are more convenient; some were made using more familiar methods and technologies. As for the claim that the vaccines have proved perfectly and equally effective at preventing hospitalization and death? It’s just not right.

‘These differences among the options could matter quite a bit, in different ways to different people, and they should not be minimized or covered over. Especially not now: Vaccine supplies in the U.S. will soon surpass demand, even as more contagious viral variants spread throughout the country. In the meantime, governors are revoking their rules on face masks, or taking other steps to loosen their restrictions. It’s tempting to believe that a simple, decisive message—even one that verges on hype—is what’s most needed at this crucial moment. But if the message could be wrong, that has consequences.’

Read here (The Atlantic, Mar 8, 2021)

Finding an ultimate vaccine to fight the mutating “emperor” virus

‘We are commenting on the shocking CNN website report (March 2), headlined “All our recent progress with COVID-19 could be wiped out by variants, CDC director says”. The first two paragraphs (below) are enough to sum up the CNN report: “The US is at risk of losing all its recent gains in the battle against COVID-19 as highly contagious variants take advantage of Americans getting lax with safety measures... “Please hear me clearly: At this level of cases with variants spreading, we stand to completely lose the hard-earned ground we have gained,” said Dr Rochelle Walensky, director of the US centers for Disease Control and Prevention (CDC).”...

‘With new variants, serious doubts are suggested by the CNN report on whether this “vaccine” [mRNA], the first in the global market, would work, even if safety factor is put aside. Nevertheless, there are safe and workable vaccines, using tried and tested technologies like using inactivated or attenuated virus from nature to stimulate the body to produce anti-body response. Even the adenovirus viral vector technology, tried and tested for Ebola, appears to be safer than mRNA.

‘There are also safe and good alternatives, like the anti-viral “broad spectrum” drug Ivermectin, which can destroy the new variants. In the meantime, it is vital that we improve our body immunity against COVID-19 by taking Vitamin C with zinc, Vitamin D, minerals and trace elements needed, explore proven traditional and complimentary medicines, and maintain established standard operating procedures (SOPs) of physical distancing, wearing surgical masks and personal hygiene in public places.’

Read here (Focus Malaysia, Mar 4, 2021)

India's Covid vaccine wins over some sceptics after promising data

‘Indian doctors and politicians on Thursday welcomed efficacy data for a state-backed coronavirus vaccine that was given emergency approval in January without the completion of a late-stage trial, making people reluctant to receive the shot.

‘Government data shows (dashboard.cowin.gov.in) that only 10% of about 13.3 million people immunised in India have taken the COVAXIN shot, which was found to be 81% effective in an interim analysis of the late-stage trial, its developer Bharat Biotech said on Wednesday.’

Read here (Reuters, Mar 4, 2021)

Covid-19: Pfizer BioNTech vaccine reduced cases by 94% in Israel, shows peer reviewed study

‘The Pfizer BioNTech coronavirus vaccine produces as good results in the “real world” as have been previously documented in randomised trials.

‘A case control study, which has been peer reviewed and published in the New England Journal of Medicine, compared 596 618 people who were newly vaccinated in Israel and matched them to unvaccinated controls.1 Two doses of the mRNA vaccine reduced symptomatic cases by 94%, hospitalisation by 87%, and severe covid-19 by 92%, according to the data from the Clalit Institute for Research which is Israel’s biggest healthcare provider.

‘Researchers recorded the outcomes at three periods: days 14 to 20 after the first dose of vaccine, days 21 through 27 after the first dose, and day 7 after the second dose. In Israel, the second dose of vaccine is given on day 21 in line with the trials and the manufacturer’s recommendation. The UK is leaving a 12 week gap between doses.

‘During a mean follow-up of 15 days, 10 561 infections were documented of which 5996 were symptomatic covid-19 illness, 369 required hospitalisation, 229 were severe cases, and 41 resulted in death.

‘After one dose, during days 14 to 20, the vaccine effectiveness was 57% for symptomatic covid-19, 74% for hospitalisation, and 62% for severe disease. The estimated effectiveness in preventing death from covid-19 was 72% in the two to three weeks after the first dose. There was insufficient data to produce an estimate on the reduction in mortality in those who received two doses.

‘The study took place from 20 December 2020, when Israel’s national vaccination drive was launched, to 1 February 2021. It coincided with Israel’s third and largest wave of coronavirus infection and illness.’

Read here (BMJ, Feb 25, 2021)

• BNT162b2 mRNA Covid-19 vaccine in a nationwide mass vaccination setting

Read original study here (New England Journal of Medicine, Feb 24, 2021)

FDA says single-dose shot from J&J prevents severe Covid

‘Johnson & Johnson’s single-dose vaccine offers strong protection against severe COVID-19, according to an analysis released Wednesday by U.S. regulators that sets the stage for a final decision on a new and easier-to-use shot to help tame the pandemic.

‘The long-anticipated shot could offer the nation a third vaccine option and help speed vaccinations by requiring just one dose instead of two. Food and Drug Administration scientists confirmed that overall the vaccine is about 66% effective at preventing moderate to severe COVID-19, and about 85% effective against the most serious illness. The agency also said J&J’s shot is safe.’

Read here (AP, Feb 25, 2021)

Viral questions

A look at some of the most commonly asked questions around the coronavirus pandemic.

• How would COVID-19 vaccine makers adapt to variants?
• How do we know the COVID-19 vaccines are safe?
• How are experts tracking variants of the coronavirus?
• Which COVID-19 tests are required for international travel?

And more...

Read here (AP, Feb 25, 2021)

The scientist who’s been right about Covid-19 vaccines predicts what’s next

‘[Hilda] Bastian — an expert in analyzing clinical trial data, founding member of the Cochrane Collaboration, and a former National Institutes of Health official — has gone down rabbit holes before. There was the time she traveled the US on her own dime to research and take historical photos for a Wikipedia list of African American mathematicians.

‘But her obsession with vaccines in this pandemic has been especially fruitful: She’s called the race right at just about every turn...

‘Nearly a year into her project, I caught up with Bastian to ask where our blind spots are now and how she predicts the vaccine story — and the pandemic — will unfold. She talked about the need for health officials to acknowledge that coronavirus vaccines have potentially “big differences in efficacy and adverse events,” a time in the future when we may need Covid-19 vaccine boosters every year, and the problem of people in rich countries like the US shamelessly hogging vaccines.’

Read here (Vox, Feb 24, 2021)

Why Covid vaccines are so difficult to compare

‘Given the demand for speed amid limited supplies, any effort to rank the vaccines must take into account not only their reported effectiveness, but also supplies, costs, the logistics of deploying them, the durability of the protection they offer and their ability to fend off emerging viral variants. Even so, many people might find it hard to look away from clinical-trial results that suggest an efficacy gap. So far, more than 200 million doses of coronavirus vaccines have been delivered, and data have been rolling in from clinical trials in several countries. The top-line results from those studies suggest a range of protection: from 95% efficacy for a vaccine made by Pfizer of New York City and BioNTech of Mainz, Germany, to about 70% suggested by initial results on a vaccine made by AstraZeneca of Cambridge and the University of Oxford, both in the United Kingdom.’

Read here (Nature, Feb 23, 2021)

Experts answer the biggest Covid vaccine questions

‘The lack of informed messaging from the Trump administration, combined with the range of different COVID vaccines, the emergence of new coronavirus variants, and inconsistent state and municipal rollout plans, have caused confusion and driven vaccine hesitancy. Scientific American asked Namandjé Bumpus, a pharmacologist at Johns Hopkins Medicine in Baltimore, and Ashley Lauren St. John, an immunologist at Duke-NUS Medical School in Singapore to answer some of the biggest questions about the currently available COVID vaccines:

• Should you get an authorized COVID vaccine now if you are eligible?
• Should you get vaccinated if you have already had COVID?
• How should you interpret vaccine efficacy—what does “95 percent efficacy” or “66 percent efficacy” even mean?
• If you get the vaccine and still get infected, does the vaccine still make a difference? 
• Will it prevent severe disease or death?
• Do the vaccines protect against the new virus variants, including those first identified in the U.K., South Africa and Brazil?
• What is the difference between mRNA and viral vector vaccines?
• Is there a “best” vaccine?
• Will the vaccine protect you from giving the virus to others?
• Will the vaccine’s effectiveness “wear off” over time?
• Should you be worried about allergic reactions to the vaccine?
• How can you ensure you’re getting a legitimate, authorized vaccine?

Read here (Scientific American, Feb 19, 2021)

Can Covid vaccines stop transmission? Scientists race to find answers

‘Controlling the pandemic will require shots that prevent viral spread, but that feature is difficult to measure...

‘Preliminary analyses suggest that at least some vaccines are likely to have a transmission-blocking effect. But confirming that effect — and how strong it will be — is tricky because a drop in infections in a given region might be explained by other factors, such as lockdowns and behaviour changes. Not only that, the virus can spread from asymptomatic carriers, which makes it hard to detect those infections.

“These are among the hardest types of studies to do,” says Marc Lipsitch, an infectious-disease epidemiologist at the Harvard T. H. Chan School of Public Health in Boston, Massachusetts. “All of us are out there, hungrily trying to see what we can get out of little bits of data that do come out,” he says. Results from some studies are expected in the next few weeks.’

Read here (Nature, Feb 19, 2021)

Israeli study finds 94% drop in symptomatic Covid-19 cases with Pfizer vaccine

‘Israel's largest healthcare provider on Sunday (Oct 14) reported a 94 per cent drop in symptomatic COVID-19 infections among 600,000 people who received two doses of the Pfizer's vaccine in the country's biggest study to date.

‘Health maintenance organization (HMO) Clalit, which covers more than half of all Israelis, said the same group was also 92 per cent less likely to develop severe illness from the virus.’

Read here (Channel News Asia, Feb 15, 2021)

Variants v Vaccines: The race between the tortoise and the hare -- Tomas Pueyo

‘The B117 variant will probably take over between February and March in most developed countries. That’s without taking into account the Brazilian and South African variants. Emerging countries are in an even worse position: Not only will they have the 3 variants. They will also receive vaccines much later. And in the Southern hemisphere, they’re now enjoying summer. Winter, with more variants and not enough vaccines, might be less forgiving.

‘So keep tight for a few more months. Don’t let your guard down. The end of the tunnel is near. Get a vaccine if you can. If not, wait till the summer. By September, we’ll likely be back to the new normal in developed countries. And in emerging ones, let’s hope more vaccines and a fast rollout avoids a repeat of 2020.’ 

Read here (substack.com, Feb 8, 2021)

Vaccine strategy needs rethink after resistant variants emerge, say scientists

‘Leading vaccine scientists are calling for a rethink of the goals of vaccination programmes, saying that herd immunity through vaccination is unlikely to be possible because of the emergence of variants like that in South Africa. The comments came as the University of Oxford and AstraZeneca acknowledged that their vaccine will not protect people against mild to moderate Covid illness caused by the South African variant. The Oxford vaccine is the mainstay of the UK’s immunisation programme and vitally important around the world because of its low cost and ease of use.

‘The findings came from a study involving more than 2,000 people in South Africa. They followed results from two vaccines, from Novavax and Janssen, which were trialled there in recent months and were found to have much reduced protection against the variant – at about 60%. Pfizer/BioNTech and Moderna have also said the variant affects the efficacy of their vaccines, although on the basis of lab studies only.

‘All the vaccines, however, have been found to protect against the most severe disease, hospitalisation and death.’

Read here (The Guardian, Feb 7, 2021)

Vaccines are curbing Covid: Data from Israel show drop in infections

‘Close to 90% of people aged 60 and older in the country have received their first dose of Pfizer’s 2-dose vaccine so far. Now, data collected by Israel’s Ministry of Health show that there was a 41% drop in confirmed COVID-19 infections in that age group, and a 31% drop in hospitalizations from mid-January to early February. In comparison, for people aged 59 and younger — of which just more than 30% have been vaccinated — cases dropped by only 12% and hospitalizations by 5% over the same time. The figures are based on analysis of roughly a quarter of a million COVID-19 infections.’

Read here (Nature, Feb 5, 2021)

Sinovac applies for conditional approval of Covid-19 vaccine in China

‘China's medicine regulator is reviewing a second domestically developed COVID-19 vaccine for conditional approval. The CoronaVac inoculation, developed by Sinovac Biotech, has been given to tens of thousands of people in China under an emergency use program launched in July targeting specific groups with high infection risks. Regulators are also reviewing for approval a similar vaccine created by state-owned China National Pharmaceutical Group, known as Sinopharm...

‘China's COVID-19 vaccines have won approval in a dozen countries for emergency use, but the failure to publish detailed trial data could undermine public trust, a leading Chinese researcher said in a recent interview.

‘Ding Sheng, dean of Tsinghua University's School of Pharmaceutical Sciences and director of the Global Health Drug Discovery Institute (GHDDI), called for the original clinical trial data from Chinese experimental vaccines to be made public so that experts can better assess their efficacy and eliminate lingering safety concerns in China and abroad.’

Read here (Nikkei, Feb 4, 2021)

Can you still transmit Covid-19 after vaccination?

‘In fact, most vaccines don't fully protect against infection, even if they can block symptoms from appearing. As a result, vaccinated people can unknowingly carry and spread pathogens. Occasionally, they can even start epidemics. 

"Effective" or "sterilising" immunity: There are two main types of immunity you can achieve with vaccines. One is so-called "effective" immunity, which can prevent a pathogen from causing serious disease, but can't stop it from entering the body or making more copies of itself. The other is "sterilising immunity", which can thwart infections entirely, and even prevent asymptomatic cases. The latter is the aspiration of all vaccine research, but surprisingly rarely achieved.

What type of immunity do the Covid-19 vaccines provide? "In a nutshell we don't know, because they’re too new," says Neal. So far, the available Covid-19 vaccines have not been judged primarily on their ability to prevent transmission – though this is now being evaluated as a secondary endpoint for many of them. Instead, their efficacy was assessed by whether they could prevent symptoms from developing. "This means that we set our targets kind of pragmatically," says Danny Altmann, professor of immunology at Imperial College London.’

Read here (BBC, Feb 4, 2021)

Could mixing Covid vaccines boost immune response?

‘Vaccine developers often combine two vaccines to combat the same pathogen, and researchers are keen to deploy the strategy — known as a heterologous prime-boost — against the coronavirus. A heterologous prime-boost combination was approved last year by European regulators to protect against Ebola, and experimental HIV vaccines often rely on the strategy, says Dan Barouch, director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Boston, Massachusetts. But it has yet to be tested for vaccines against COVID-19, which are typically given as a repeat injection of the same vaccine.

‘The ability to mix and match vaccines could make vaccination programmes more flexible: it would speed up the process and reduce the impact of any supply-chain disruptions. “It really makes the implementation much more simple,” said Mary Ramsay, head of immunization at Public Health England, at a press briefing on 3 February.’

Read here (Nature, Feb 4, 2021)

Covid-19 infection rates fall as millions are vaccinated in Britain

‘Infection rates in the over-80s have fallen by 36 per cent this month. Other age groups have seen similar falls. The biggest drop was recorded in people in their 20s. Rates in that age group have halved. Prof Harnden said: “The data we have is still is very early because it only reflects approximately three or four weeks of the program and it’s mainly based on the Pfizer vaccine.”

Read here (News.com, Feb 1, 2021)

Sputnik V ‘91·6% efficacious, well tolerated’: Safety and efficacy of an rAd26 and rAd5 vector-based heterologous prime-boost COVID-19 vaccine: an interim analysis of a randomised controlled phase 3 trial in Russia

‘Our interim results of the phase 3 Gam-COVID-Vac trial show that the vaccine is 91·6% (95% CI 85·6–95·2) efficacious against COVID-19 (from day 21 after first dose, the day of receiving second dose). Our results also showed that the vaccine was 100% (95% CI 94·4–100) efficacious against severe COVID-19, although this was a secondary outcome so the results are preliminary. The vaccine was well tolerated, with 45 (0·3%) of 16 427 participants in the vaccine group reporting serious adverse events, all of which were considered not related to the vaccine... 

‘The vaccine induced robust humoral (n=342) and cellular (n=44) immune responses in all age strata. Notably, there were a few non-responders in the vaccine group (six of 342), possibly due to immunosenescence in older people, individual characteristics of the formation of an immune response, or concomitant immunological disorders.’

Read here (The Lancet, Feb 2, 2021)