In Israel, Infections Drop Sharply After One Shot of Vaccine

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In Israel, Infections Drop Sharply After One Shot of Vaccine

JERUSALEM – Israel, the world leader in vaccinating its population against the coronavirus, has brought out some encouraging news: Early results show a significant decrease in infection after just one shot of a two-dose vaccine and better than expected results after both doses.

Public health experts warn that the data based on the Pfizer BioNTech vaccine are preliminary and have not been subjected to clinical studies. Nevertheless, Dr. Anat Ekka Zohar, Vice President of Maccabi Health Services, one of the Israeli health maintenance organizations that released the data, called them "very encouraging".

In the first early report, Clalit, Israel's largest health fund, compared 200,000 people aged 60 and over who had received a first dose of the vaccine to a corresponding group of 200,000 who had not yet been vaccinated. The partially vaccinated patients were said to be 33 percent less likely to be infected 14 to 18 days after their shots.

Around the same time, Maccabi's research branch said they saw an even greater decrease in infections after just one dose: a decrease of about 60 percent, 13 to 21 days after the first shot, in the first 430,000 people to receive it .

Maccabi did not provide an age group or whether the data were compared to a matching, unvaccinated cohort.

On Monday, the Israeli Ministry of Health and Maccabi released new data on people who received both doses of vaccine, showing extremely high rates of effectiveness.

The ministry found that of 428,000 Israelis who received their second dose, only 63, or 0.014 percent, contracted the virus a week later. Similarly, the Maccabi data showed that more than a week after receiving the second dose, only 20 out of approximately 128,600 people, about 0.01 percent, had the virus.

In clinical studies, after two doses, the Pfizer vaccine was shown to be 95 percent effective in preventing coronavirus infection in people with no evidence of previous infection. The Israeli results suggest that effectiveness could be even higher, although rigorous comparisons with unvaccinated people have not yet been published.

"This is very encouraging data," said Dr. Zohar. "We will closely monitor these patients to see if they continue to have mild symptoms and do not develop complications from the virus."

Both Clalit and Maccabi warned that their results were preliminary and said they would soon be followed by more in-depth statistical analysis in peer-reviewed scientific publications.

Israel, where more than 40 percent of the population has already received a first dose of the vaccine, has become an international test case for the effectiveness of the vaccine.

With its small population, highly digitized universal health system, and rapid adoption of military-backed vaccines, Israel's real world data provides a useful addition to clinical trials for researchers, pharmaceutical companies, and policy makers.

Israel has signed a contract with Pfizer under which the pharmaceutical company ensured the country an early and steady supply of vaccines in exchange for data. The Ministry of Health has published an edited version of the agreement.

Despite its race to vaccinate, Israel is suffering from a devastating third wave of the coronavirus. The government put a strict national lockdown this month after weeks of infections and deaths.

Israel should suspend most air travel in and out of the country from midnight Monday to block the arrival of newly emerging virus variants that could jeopardize the country's vaccination campaign. Two vaccine manufacturers said Monday that their vaccines were a little less effective against one of the new variants.

Such real-world data from Israel, while useful, is subject to variables that may skew results and that clinical studies should take into account.

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Answers to your vaccine questions

If I live in the US, when can I get the vaccine?

While the exact order of vaccine recipients may vary from state to state, most doctors and residents of long-term care facilities will come first. If you want to understand how this decision is made, this article will help.

When can I get back to normal life after the vaccination?

Life will not return to normal until society as a whole receives adequate protection against the coronavirus. Once countries approve a vaccine, they can only vaccinate a few percent of their citizens in the first few months. The unvaccinated majority remain susceptible to infection. A growing number of coronavirus vaccines show robust protection against disease. However, it is also possible for people to spread the virus without knowing they are infected because they have mild or no symptoms. Scientists don't yet know whether the vaccines will also block the transmission of the coronavirus. Even vaccinated people have to wear masks for the time being, avoid the crowds indoors and so on. Once enough people are vaccinated, it becomes very difficult for the coronavirus to find people at risk to become infected. Depending on how quickly we as a society achieve this goal, life could approach a normal state in autumn 2021.

Do I still have to wear a mask after the vaccination?

Yeah, but not forever. The two vaccines that may be approved this month clearly protect people from contracting Covid-19. However, the clinical trials that produced these results were not designed to determine whether vaccinated people could still spread the coronavirus without developing symptoms. That remains a possibility. We know that people who are naturally infected with the coronavirus can spread it while they don't have a cough or other symptoms. Researchers will study this question intensively when the vaccines are introduced. In the meantime, self-vaccinated people need to think of themselves as potential spreaders.

Will it hurt What are the side effects?

The vaccine against Pfizer and BioNTech, like other typical vaccines, is delivered as a shot in the arm. The injection is no different from the ones you received before. Tens of thousands of people have already received the vaccines, and none of them have reported serious health problems. However, some of them have experienced short-lived symptoms, including pain and flu-like symptoms that usually last a day. It is possible that after the second shot, people will have to plan to take a day off or go to school. While these experiences are not pleasant, they are a good sign: they are the result of your own immune system's encounter with the vaccine and a strong reaction that ensures lasting immunity.

Will mRNA vaccines change my genes?

No. Moderna and Pfizer vaccines use a genetic molecule to boost the immune system. This molecule, known as mRNA, is eventually destroyed by the body. The mRNA is packaged in an oily bubble that can fuse with a cell, allowing the molecule to slide inside. The cell uses the mRNA to make proteins from the coronavirus that can stimulate the immune system. At any given point in time, each of our cells can contain hundreds of thousands of mRNA molecules that they produce to make their own proteins. As soon as these proteins are made, our cells use special enzymes to break down the mRNA. The mRNA molecules that our cells make can only survive for a few minutes. The mRNA in vaccines is engineered to withstand the cell's enzymes a little longer, so the cells can make extra viral proteins and trigger a stronger immune response. However, the mRNA can hold for a few days at most before it is destroyed.

The early Israeli numbers are based on the first people to receive the vaccine. Such people, experts say, are likely to be more concerned or informed about the virus, and therefore more cautious about social distancing and wearing masks. They could also differ from those who did not hurry to determine the location and socio-economic status.

Experts also say that the disease changes over time. Prof. Ran Balicer, the chief innovation officer at Clalit and a leading Israeli epidemiologist, said two-week-old data may be like evidence from another time or "about a million vaccines in Israeli terms".

Maccabi said it would publish more data every week. "The main message," Maccabi said in a statement, is that the first dose of the vaccine "is effective, reducing morbidity and hospital stays by tens of percent."

Experts warn that the release of raw data can be misinterpreted.

After Clalit first released its early numbers two weeks ago, many people heard of a 33 percent decrease in cases, not the 95 percent expected, and came to the wrong conclusion that the Pfizer shot wasn't working.

There has been an uproar in the UK with authorities delaying delivery of the second dose by up to 12 weeks, in contrast to the 21-day hiatus on which Pfizer based its attempts.

Professor Balicer considered the results to be good news and was dismayed by how they were interpreted.

"We were calm enough to tell everyone we see what we should see right after day 14," he said. "I don't know how this turned into a message of, 'Oh my god, it doesn't work'."

Professor Balicer, who also chairs the team of experts advising the Israeli government on its response to Covid-19, hoped the positive results could have an impact on an upcoming government decision on a third lockdown.

"Covid has turned us all into amateur scientists," said Talya Miron-Shatz, associate professor and medical decision-making expert at Ono Academic College in central Israel. "We all look at data, but most people aren't scientists."

Israel, which began vaccinating people on December 20, gave an initial shot to more than 2.6 million Israelis and both shots more than a million people.

After starting out with people aged 60 and over, healthcare workers, and other high-risk individuals, Israel now offers vaccinations for people over 40 and students ages 16-18 so they can go back to school. The military is supporting the effort and 700 army reserve medical personnel are helping at vaccination centers.

Prof. Jonathan Halevy, the president of Shaare Zedek Medical Center in Jerusalem, had not examined the H.M.O.'s results, but said he had noticed a decrease in severe cases two weeks after the first dose was introduced.

"I know several people who got infected shortly before the vaccine, but they got it easily," he said.

Still, Israel remains under a national lockdown and officials are concerned about the emergence of new, highly contagious variants. It remains to be seen how effective the vaccines will be against the new variants.

Despite the vaccine's seemingly early success, the virus continues to wreak havoc in Israel. Professor Halevy said his hospital's Covid wards are still full and he anticipates it would take another two or three weeks for a decline to occur.

The virus has killed more than 1,000 Israelis this month alone, nearly a quarter of those who died from the pandemic virus in total.

Health officials and experts have attributed much of the recent surge in infection to the fast-spreading variant, which was first discovered in the UK.

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