Israel has witnessed a recent spike in COVID-19 cases, primarily due to the delta variant entering the country through international travellers. The spike in cases is of particular concern to government officials. A majority of the new cases are among those that have completed their two-dose vaccination regimen. 

Recent non peer-reviewed data released by the Israeli government showed significant drops in protection for fully vaccinated people against: 

a) infection from SARS-CoV-2 (from 75% to 39%)  b) symptomatic COVID-19 (from 79% to 41%) 

This is primarily due to the emergence of the more contagious delta variant. Protection against hospitalizations and severe COVID-19, however, did not drop significantly. These preliminary data require further investigation in order 

The delta variant spreads much easier (~50% greater) than earlier strains. This, coupled with recent relaxation in protective measures like indoor masking mandates likely contributed to the new cases, especially breakthrough cases amongst fully vaccinated people. 

In July the Israeli government distributed a third dose of the Pfizer-BioNTech vaccine to immunocompromised individuals. The government is now distributing a third dose to those over the age of 60. This decision is based on data initially analyzed by Pfizer-BioNTech during the vaccine’s phase 3 trials. The data showed that around four to six months after receiving a second dose, there may be a drop in protection against symptomatic infection. This is yet to be corroborated with real-world data, since the delta variant emerged more recently than the clinical trial.

There have been no large-scale studies to date that have examined the potential side-effects of a third dose of the Pfizer-BioNTech vaccine, but it is likely that there may be more acute episodes of the common side effects that tend to happen after a second dose (e.g. headaches, tiredness, muscle pain, fevers, swelling). There is no evidence to show that a third dose would cause increased rates of cancers, heart attacks, or death among those vaccinated. 

The CDC and FDA in the United States remain confident that a two-dose regimen is sufficient at this time, and are focused on expanding the population of those fully vaccinated with two doses. They are also currently examining the need for a third dose among US populations.

More broadly, experts believe that the push for a third dose in wealthier nations with already high rates of vaccination will only exacerbate the global disparities in access to COVID-19 vaccines. 

A recent spike in cases linked to the spread of the delta variant of SARS-CoV-2 in Israel has led to a change in government policy regarding a third dose of the Pfizer-BioNTech mRNA vaccine among certain vulnerable populations. 

This decision to offer a booster dose to vulnerable populations has coincided with viral videos claiming that a third dose will have severe side effects including heightened rates of cancers, heart attacks and deaths.