With a surge of Covid-19 infections at the highest levels since February, Israel is now contemplating further lockdowns and the possibility of extending booster vaccine shots to those over 50 years old. This comes after administering booster shots to about 2,000 immunocompromised people weeks ago before extending the shots to all those over 60 on August 1. Cases are occurring in both vaccinated and unvaccinated populations, yet with one of the highest vaccination rates in the world, Israel’s experience confirms that no single modality will control Covid-19 alone, as the virus continues to evolve and mutate. We need a multi-modal strategy to contain Covid-19.
A July report from the Israel Ministry of Health found that Pfizer/BioNTech’s Covid-19 vaccine is just 39% effective in Israel, where the Delta variant is the dominant strain but still provides strong protection against severe illness and hospitalization. According to the report, the vaccines still work very well in preventing severe cases, demonstrating 88% effectiveness against hospitalization and 91% effectiveness against severe illness. But this is still is a steep decline from the earlier estimate of 64% efficacy rate released on July 5, and steeper still from the initial 95% efficacy rate Israel published in May, based on records from Jan. 24 to April 3, 2021.
The Israel report contrasts with data from the UK government that shows the Pfizer/BioNTech vaccine was 88% effective against symptomatic disease from the Delta variant two weeks after the second dose, compared to 93% effectiveness against the Alpha Variant during the period from 5 April to 16 May.
As one of the quickest countries to roll out the vaccine, Israel acts as the canary in the coal mine for us all, especially in the United States, where we have few other modes of public health protections. As weary as many of us are about Covid protocols and interventions, we must not remain complacent, as this virus is far from running out of tricks.
Israel once had a robust contact tracing system that kept the virus under control even before the vaccines were available. In late May, spurred on by false confidence from low daily cases rates and the swift vaccine rollout, Defense Minister Benny Gantz and military chief Aviv Kochavi closed the army’s contact-tracing center, known as Alon, transferring the responsibility to the Health Ministry and slashing staff. At the height of its operations, Alon had around 3,000 contact tracers capable of carrying out 6,000 epidemiological investigations a day. With 10,000 new cases reported in Israel over the last few days, contact tracers were only able to conduct epidemiological investigations on 40 percent of cases.
There has been a strong focus recently by Israel and many other countries on booster shots as a solution to waning vaccine immunity. But we cannot make the mistake of relying on one modality, vaccines are a critical tool in our fight against Covid-19, but they must be paired with other layers of protection. To fill any gaps in vaccine protection, we can create a second layer of defense with the prophylactic use of antiviral drugs.
The US government recently committed $3.2 billion to develop antiviral pills for Covid-19. While this is a valuable contribution, we urgently need to supercharge the development of antiviral drugs with the same priority we did for vaccines. Many have focused on antiviral drugs purely as a treatment for Covid-19, when their real power is in their prophylactic use, preventing people exposed to the virus from ever becoming ill or passing on an infection. Similar to how Xofluza, an antiviral used for Influenza reduces transmission by 80% in a close-quarter family context. With a good safety profile, antiviral drugs could be taken by anyone exposed to Covid-19 in a congregate living situation. By attacking the virus before it has a chance to replicate we have the opportunity to prevent the spread of infections and mutation of future variants. Of course, for this prophylactic use of antivirals to be successful it needs to be combined with a mass rapid antigen testing and robust contact tracing program to quickly determine exposure.
As the virus continues to evolve so must our defense strategy. A multimodal strategy that utilizes antiviral drugs ensures that we can protect our current population and rebuild a world that is prepared for future Covid and other disease outbreaks.