Despite high vaccination rates, analysis shows a definite positive impact, but patience is needed to see the real-world impacts in Israel, a pattern that may hold true in other countries also.
Vaccination programs to combat coronavirus disease 2019 (COVID-19) have gained momentum around the world. Some countries have prioritized vaccines first for the elderly and healthcare workers, while several other countries have opened up the vaccine to all adults.
Israel started vaccinating its population starting December 2020 with the Pfizer-BioNTech mRNA vaccine, first prioritizing those above 60 years and others at a higher risk of severe COVID-19. Gradually over the month of January 2021, the vaccination was opened up to all, including young adults (16–18-year-olds). Starting 4 February 2021, everyone above 16 years became eligible to receive the vaccine.
This rapid rate of vaccination made Israel the country with the highest number of vaccinated people per capita. This was made possible for several reasons, like Israel’s small geographic size, outreach, availability of sufficient doses, a public health system, and community-based nurses.
However, vaccination rates were also dependent on socioeconomic status. The daily vaccination rates decreased once the majority of the higher-risk population was vaccinated, as younger people were more reluctant to take the vaccine.
Assessing real-life impact
The Phase III clinical trials of the vaccine indicated a 95% protection against COVID-19 when two doses were administered 21 days apart. However, this does not directly translate to a similar effect on the population. The real-life impact on individuals and the impact on the larger population needs to be studied further, and the results may be different from those obtained in the clinical trials.
The real-life impact may differ because of a non-uniform effect depending on the population, not keeping to vaccination schedules, and inadequate handling of the vaccine. The larger-scale effect also depends on vaccine coverage, allocation of doses among different groups, and how the different groups mix socially.
In the early weeks of vaccination in Israel, the government imposed a lockdown, and new, more transmissible strains emerged, making it difficult to assess the effect of vaccination. However, after two months of vaccination, some data is emerging on the effectiveness.
One report estimated a 51% relative risk reduction 13–24 days after the first dose of the vaccine. Another study compared newly vaccinated and unvaccinated controls and found 46% effectiveness 14–20 days after the first dose and 92% seven days after the second dose.
“These findings are encouraging, showing consistency between real-life effectiveness and the results reported in the randomized control trial,” write the authors in a comment published in Nature Reviews Immunology.
Upon analyzing data, the authors found a large and early decrease in the number of hospitalizations and cases among the elderly, who received the vaccine first. Cities that started vaccinating first showed this trend much more clearly. Furthermore, there was a shift to lower age groups among the hospitalizations. Adolescents 16 to 18 years who were also vaccinated showed lower positivity rates than 13–15-year-olds.
Trends may be similar in other countries
A modeling analysis also showed a decrease in the number of severe cases, mainly in those over 60 years, which occurred about a week before if only lockdowns were implemented. Although the clinical trial data showed the vaccine was effective as soon as two weeks after the first dose, real-life data indicate it may take about 3–4 weeks at the population level.
Vaccination implementation strategy should take into account the allocation and prioritization of different groups to ensure effectiveness at the population level. After prioritizing people at the highest risk category, priority should be given to people who are not at risk of severe disease but have a greater probability of transmitting the virus more.
In addition, strategies to reduce reluctance, especially among the younger population, must also be considered. The Israel government used many ways to do this, for example, opening vaccine centers at night, setting them up in nature reserves on weekends, and free meals.
Thus, as the data from Israel show, patience is needed to see the results of vaccination at the population level, despite high vaccination levels and lockdowns, and such a trend may also hold true for other countries.
It must also be emphasized to the public that vaccination does not provide total protection, especially only after one dose, and people must follow public prevention guidelines. Communicating the real-life impacts is also important as the positive trends build trust and ensure continued vaccination.