Even after one dose of the Pfizer-BioNTech vaccine, people who become infected with Covid-19 present a much lower transmission risk, new Israeli research reveals.

This is because the vaccine appears to lower the viral load four-fold for infections occurring 12 to 28 days after the first of two doses, according to a paper published online by a group supported by the Israel Science Foundation’s KillCorona-Curbing Coronavirus Research Program.

The paper, which is not yet peer reviewed, was written by scientists from Technion-Israel Institute of Technology and Maccabi Research Institute.

Conclusions were based on positive post-vaccination data from Maccabi Healthcare Services, the second largest of Israel’s four national health maintenance organizations.

This follows another Israeli study indicating that people over 60 who are fully vaccinated against Covid-19 are less likely to transmit the coronavirus to others. Data from two testing labs showed that vaccination reduces the viral load by 1.6 to 20 times in individuals who are positive for SARS-CoV-2.

Taken together, the two studies raise hopes that people who are vaccinated protect not only themselves but also those around them from developing serious symptoms of Covid-19.

This may hasten Israel’s reaching herd immunity, which happens when a sufficient percentage of a population has immunity and gives indirect protection to those who aren’t immunized.

Herd immunity is an important question in Israel. Although the country has vaccinated more people per capita than any other country – 65.83 as of February 8 — some 30 percent of the population is under 16 and therefore cannot be vaccinated for Covid-19.