Analysis from Israel reveals that the mRNA vaccine is ~ 50% efficient in decreasing extreme circumstances
Amid the coronavirus disease (COVID-19) pandemic caused by the severe coronavirus 2 (SARS-CoV-2) with acute respiratory syndrome, there is a glimmer of hope as vaccinations against the virus are introduced in many countries.
Israel is one of the countries that has started vaccinating its residents. The country has given more than 55 doses of the Pfizer or Moderna vaccine per 100 residents. A third of the population has already received at least the first dose of the previously required two doses.
In a report published on the pre-print server medRxiv *, researchers from the Hebrew University of Jerusalem, the University of Trento and the Racah Institute of Physics suggest that the shape of the outbreak in patients over 60 years of age is due to vaccinations.
Since the introduction of vaccination in Israel, new moderate and severe cases have decreased by about a week earlier than expected.
Effective Reproduction Number Re in Israel, estimated using the 4-day growth factor of daily confirmed cases, with respect to the start of national lockdowns on either September 19, 2020 (gray line) or January 8, 2021 (black line)). The shaded area indicates 1.5 standard deviations of the black line. One observes the remarkable similarity between Re, which represents the dynamics of the eruption, between the two locks.
Israel's COVID-19 vaccination campaign
Approximately every third inhabitant of Israel has had a vaccination against COVID-19 since December 19, 2021. The country's prime minister, Binyamin Netanyahu, has campaigned heavily on vaccinations and negotiated personally with Pfizer, a pioneer in developing a COVID-19 vaccine to ensure early vaccine deliveries.
The campaign prioritized people aged 60 and over, immunodeficient patients, and health workers. By January 25, 2021, approximately 2.6 million Israelis, or 29 percent of the population, had been vaccinated with at least the first dose. The second dose is introduced and gives 80 percent vaccine coverage.
New daily moderate and severe cases in patients over 60 years of age in January Ineligibility (blue) and September Ineligibility (red). The bars indicate the percentage of vaccinated people who are older than 60 years, based on the blocking in January. The time difference of about 8 days between the peaks is an indication of the effectiveness of the vaccination.
With the rapid introduction of the vaccine, there is evidence that the program is having a significant impact on virus transmission in the country. The cases of COVID-19 in Israel fall among older adults who were among the first to receive their vaccines.
Hospital admissions among those over 60 have declined 26 percent since peaking on Jan. 19. However, among those between 40 and 59, the age group in the queue for vaccinations, the number of severe cases increases by 13 percent.
The new daily moderate and severe cases for three different vaccine effectiveness scenarios and no vaccines. Solid line: Long-acting lockout with an effective vaccine. Dashed (dotted) line: Long effective lockout with 95% (50%) effectiveness in preventing morbidity without preventing infection.
Effectiveness of vaccines in pandemic relief
Israel is a perfect example to determine the effectiveness of vaccination against SARS-CoV-2 in reducing the number of cases, especially moderate to severe cases that require hospitalization.
To get to the results of the study, the team used data analysis to model the epidemic dynamics in the country and compare different scenarios for lockdown duration and effectiveness. The team modeled each scenario with and without vaccine coverage.
In addition, the researchers examined the daily trends of new confirmed cases, including new moderate or severe COVID-19 cases in Israel.
Moderate cases are patients with COVID-19 who developed bilateral pneumonia. Severe cases are COVID-19 with an oxygen saturation below 93 percent when breathing in the ambient air. In these cases, there is a higher risk of deterioration in health, with a death rate of 15 to 20 percent within ten days.
The team also found that on average, moderate and severe COVID-19 recordings occur about five days after a positive test and about ten days after the infection actually started. Therefore, the number of new and severe COVID-19 cases can provide insight into the dynamics of the disease.
The study also looked at trends in moderate and severe cases as potential measures of disease dynamics and the effect of the vaccine on the outbreak.
The study results showed that based on the daily new moderate and severe cases in patients over 60, the shape of the COVID-19 outbreak has changed due to vaccination efforts. The decline in new moderate and severe cases came an estimated week earlier than expected.
The team also found that the study results are consistent with the theory that vaccination results in greater than 50 percent protection in the prevention of clinical disease. It is also effective in stopping the transmission of the virus in older adults.
Overall, researchers believe that vaccinating the most vulnerable populations, including the elderly and those at high risk, can help reduce serious cases and deaths associated with COVID-19.
"This is the first indication of the effectiveness of the COVID-19 vaccine in changing the course of an ongoing pandemic outbreak," the researchers noted in the article.
Vaccination efforts are critical to fighting the pandemic and stopping the ongoing pandemic. To date, the total number of cases has reached over 106 million, with more than 2.3 million deaths worldwide.
* Important NOTE
medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be considered conclusive, guide clinical practice / health-related behavior, or treated as established information.