Studies Show Power of Pfizer Vaccine Starts to Wane After Two Months

Two new studies confirm that the immunity offered by two doses of Pfizer’s coronavirus vaccine drops off after about two months, although protection against severe disease, hospitalization and death holds strong.

The reports, from Israel and Qatar, add to evidence that suggests even fully vaccinated people need to continue to guard against COVID-19 infection.

In one study, Israeli researchers found that antibody levels among 4,800 health care workers fell rapidly within months after two doses of the Pfizer vaccine, “especially among men, among persons 65 years of age or older, and among persons with immunosuppression.”

That study also found that that immunity lasts longer in people who are vaccinated after natural COVID-19 infection.

In the other study of Pfizer’s vaccine, researchers in Qatar found that “protection against infection builds rapidly after the first dose, peaks in the first month after the second dose, and then gradually wanes in subsequent months,” Laith Abu-Raddad, of Weill Cornell Medicine-Qatar, and colleagues wrote.

“The waning appears to accelerate after the fourth month, to reach a low level of approximately 20% in subsequent months,” they added.

However, the researchers also found that protection against hospitalization and death remained above 90%.

The vaccine’s weakening protection may be due to people’s behavior, the study authors noted.

“Vaccinated persons presumably have a higher rate of social contact than unvaccinated persons and may also have lower adherence to safety measures,” they wrote. “This behavior could reduce real-world effectiveness of the vaccine as compared with its biologic effectiveness, possibly explaining the waning of protection.”

The studies were published Wednesday in the New England Journal of Medicine.

Pfizer has been saying that immunity from the first two doses of its vaccine begins to wear off after a few months, CNN reported. Last month, the U.S. Food and Drug Administration approved emergency use of booster doses of Pfizer’s vaccine six months after high-risk people finish their first two doses.

Meanwhile, the U.S. Centers for Disease Control and Prevention has recommended booster shots for people over 65, people with medical conditions that raise their risk of severe COVID-19, and people at high risk of coronavirus infection because of their jobs.

In the United States, more than 6 million people have already received a third dose of vaccine. On average, the CDC says, the pace of booster shots is now higher than the rate of people getting vaccinated for the first time, CNN reported.

Source: HealthDay

Increases in COVID-19 Are Unrelated to Levels of Vaccination Across 68 Countries and 2947 Counties in the United States

S. V. Subramanian and Akhil Kumar wrote . . . . . . . . .

Vaccines currently are the primary mitigation strategy to combat COVID-19 around the world. For instance, the narrative related to the ongoing surge of new cases in the United States (US) is argued to be driven by areas with low vaccination rates. A similar narrative also has been observed in countries, such as Germany and the United Kingdom. At the same time, Israel that was hailed for its swift and high rates of vaccination has also seen a substantial resurgence in COVID-19 cases. We investigate the relationship between the percentage of population fully vaccinated and new COVID-19 cases across 68 countries and across 2947 counties in the US.

Methods

We used COVID-19 data provided by the Our World in Data for cross-country analysis, available as of September 3, 2021 (Supplementary Table 1). We included 68 countries that met the following criteria: had second dose vaccine data available; had COVID-19 case data available; had population data available; and the last update of data was within 3 days prior to or on September 3, 2021. For the 7 days preceding September 3, 2021 we computed the COVID-19 cases per 1 million people for each country as well as the percentage of population that is fully vaccinated.

For the county-level analysis in the US, we utilized the White House COVID-19 Team data, available as of September 2, 2021. We excluded counties that did not report fully vaccinated population percentage data yielding 2947 counties for the analysis. We computed the number and percentages of counties that experienced an increase in COVID-19 cases by levels of the percentage of people fully vaccinated in each county. The percentage increase in COVID-19 cases was calculated based on the difference in cases from the last 7 days and the 7 days preceding them. For example, Los Angeles county in California had 18,171 cases in the last 7 days (August 26 to September 1) and 31,616 cases in the previous 7 days (August 19–25), so this county did not experience an increase of cases in our dataset. We provide a dashboard of the metrics used in this analysis that is updated automatically as new data is made available by the White House COVID-19 Team (https://tiny.cc/USDashboard).

Findings

At the country-level, there appears to be no discernable relationship between percentage of population fully vaccinated and new COVID-19 cases in the last 7 days (Fig. 1). In fact, the trend line suggests a marginally positive association such that countries with higher percentage of population fully vaccinated have higher COVID-19 cases per 1 million people. Notably, Israel with over 60% of their population fully vaccinated had the highest COVID-19 cases per 1 million people in the last 7 days. The lack of a meaningful association between percentage population fully vaccinated and new COVID-19 cases is further exemplified, for instance, by comparison of Iceland and Portugal. Both countries have over 75% of their population fully vaccinated and have more COVID-19 cases per 1 million people than countries such as Vietnam and South Africa that have around 10% of their population fully vaccinated.

Enlarge image . . . . .

Relationship between cases per 1 million people (last 7 days) and percentage of population fully vaccinated across 68 countries as of September 3, 2021

Across the US counties too, the median new COVID-19 cases per 100,000 people in the last 7 days is largely similar across the categories of percent population fully vaccinated (Fig. 2). Notably there is also substantial county variation in new COVID-19 cases within categories of percentage population fully vaccinated. There also appears to be no significant signaling of COVID-19 cases decreasing with higher percentages of population fully vaccinated (Fig. 3).

Enlarge image . . . . .

Median, interquartile range and variation in cases per 100,000 people in the last 7 days across percentage of population fully vaccinated as of September 2, 2021

Enlarge image . . . . .

Percentage of counties that experienced an increase of cases between two consecutive 7-day time periods by percentage of population fully vaccinated across 2947 counties as of September 2, 2021

Of the top 5 counties that have the highest percentage of population fully vaccinated (99.9–84.3%), the US Centers for Disease Control and Prevention (CDC) identifies 4 of them as “High” Transmission counties. Chattahoochee (Georgia), McKinley (New Mexico), and Arecibo (Puerto Rico) counties have above 90% of their population fully vaccinated with all three being classified as “High” transmission. Conversely, of the 57 counties that have been classified as “low” transmission counties by the CDC, 26.3% (15) have percentage of population fully vaccinated below 20%.

Since full immunity from the vaccine is believed to take about 2 weeks after the second dose, we conducted sensitivity analyses by using a 1-month lag on the percentage population fully vaccinated for countries and US counties. The above findings of no discernable association between COVID-19 cases and levels of fully vaccinated was also observed when we considered a 1-month lag on the levels of fully vaccinated.

We should note that the COVID-19 case data is of confirmed cases, which is a function of both supply (e.g., variation in testing capacities or reporting practices) and demand-side (e.g., variation in people’s decision on when to get tested) factors.

Interpretation

The sole reliance on vaccination as a primary strategy to mitigate COVID-19 and its adverse consequences needs to be re-examined, especially considering the Delta (B.1.617.2) variant and the likelihood of future variants. Other pharmacological and non-pharmacological interventions may need to be put in place alongside increasing vaccination rates. Such course correction, especially with regards to the policy narrative, becomes paramount with emerging scientific evidence on real world effectiveness of the vaccines.

For instance, in a report released from the Ministry of Health in Israel, the effectiveness of 2 doses of the BNT162b2 (Pfizer-BioNTech) vaccine against preventing COVID-19 infection was reported to be 39%, substantially lower than the trial efficacy of 96%. It is also emerging that immunity derived from the Pfizer-BioNTech vaccine may not be as strong as immunity acquired through recovery from the COVID-19 virus. A substantial decline in immunity from mRNA vaccines 6-months post immunization has also been reported. Even though vaccinations offers protection to individuals against severe hospitalization and death, the CDC reported an increase from 0.01 to 9% and 0 to 15.1% (between January to May 2021) in the rates of hospitalizations and deaths, respectively, amongst the fully vaccinated.

In summary, even as efforts should be made to encourage populations to get vaccinated it should be done so with humility and respect. Stigmatizing populations can do more harm than good. Importantly, other non-pharmacological prevention efforts (e.g., the importance of basic public health hygiene with regards to maintaining safe distance or handwashing, promoting better frequent and cheaper forms of testing) needs to be renewed in order to strike the balance of learning to live with COVID-19 in the same manner we continue to live a 100 years later with various seasonal alterations of the 1918 Influenza virus.

Source: Springer

Data Doesn’t Support Need for COVID-19 Vaccine Boosters: Experts

COVID-19 vaccine booster shots might not be needed for most people, according to a large international review.

The review — conducted by a team that included scientists from the World Health Organization and the U.S. Food and Drug Administration — concluded that current vaccines are effective enough against severe COVID-19, even from the Delta variant, and that booster shots are unnecessary.

The findings, published in The Lancet, are based on a review of all available published literature and results of clinical trials.

“The vaccines that are currently available are safe, effective, and save lives,” said study co-author Dr. Soumya Swaminathan, chief scientist at the WHO.

“Although the idea of further reducing the number of COVID-19 cases by enhancing immunity in vaccinated people is appealing, any decision to do so should be evidence-based and consider the benefits and risks for individuals and society,” she said in a journal news release. “These high-stakes decisions should be based on robust evidence and international scientific discussion.”

According to the review, vaccines were 95% effective against severe disease both from the Delta and Alpha variant, and more than 80% effective at protecting against infection from these variants.

Vaccines are less effective against asymptomatic disease or transmission than against severe disease, according to the review. It added that unvaccinated people are the major drivers of transmission and are at the greatest risk of severe disease.

“Taken as a whole, the currently available studies do not provide credible evidence of substantially declining protection against severe disease, which is the primary goal of vaccination,” said lead author Dr. Ana Maria Henao-Restrepo, a medical officer at the WHO’s Initiative for Vaccine Research.

She said the limited supply of vaccine will save the most lives if made available to unvaccinated people who are at risk of serious disease.

“Even if some gain can ultimately be obtained from boosting, it will not outweigh the benefits of providing initial protection to the unvaccinated,” Henao-Restrepo added. “If vaccines are deployed where they would do the most good, they could hasten the end of the pandemic by inhibiting further evolution of variants.”

Although antibodies in vaccinated people wane over time, the authors noted that it does not predict that a lack of protection against severe disease.

Protection against severe disease is not only from antibody responses, which might be short-lived for some vaccines, but also by memory responses and cell immunity, which are longer-lived, the researchers explained. If boosters are needed, they would be in circumstances where the benefits outweigh the risks.

Even without any loss of effectiveness, however, increasing success in delivering vaccines to large populations will lead to increasing more widespread immunization, the researchers said. As a result, more cases that do occur would be less severe breakthrough infections, especially if vaccination leads people to change their behavior.

But, they added, the ability of vaccines to elicit an antibody response against current variants indicates that these variants have not yet evolved so much they are likely to escape the protection by the vaccines.

If boosters are needed, the researchers said, they would most likely be developed against specific variants not covered by current vaccines. This strategy is like that for flu shots, which changes as flu strains evolve from year to year.

Source: HealthDay

More Than 100 Ontario Youth Sent to Hospital for Vaccine-related Heart Problems

Anthony Furey wrote . . . . . . . . .

A report quietly released last week by Public Health Ontario (PHO) tallies the number of people in the province who have presented to hospital with heart inflammation following mRNA vaccination, and it skews heavily towards young people.

As of Aug. 7, there were 106 incidents of myocarditis/pericarditis in Ontarians under the age of 25. That’s slightly more than half of the total of all such incidents.

Broken down further, 31 of these cases were in 12- to 17-year-olds and 75 were in 18- to 24-year-olds. The vast majority — 80% — were in males.

The report explains that PHO issued a directive in June for public health units to increase their surveillance of this side effect following reports from the United States and Israel of similar concerns unfolding in those countries.

“The reporting rate of myocarditis/pericarditis was higher following the second dose of mRNA vaccine than after the first, particularly for those receiving the Moderna vaccine as the second dose of the series (regardless of the product for the first dose),” the report explains.

PHO adds that the reporting rate for heart inflammation in those 18-24 was seven times higher with Moderna than with Pfizer. (The only vaccine currently used for 12- to 17-year-olds in Ontario is Pfizer.)

While PHO initially worked with reports of 314 such incidents, upon further investigation they narrowed that number down to just over 200.

There have in total been 202 emergency room visits across all age groups for such issues following vaccination, with 146 leading to hospitalization. Three of these have led to ICU admission.

When it comes to older age brackets, there were 54 persons aged 25-39 included in the tally and 44 persons aged 40 and over.

When broken down by the number of overall people who have received the vaccines, the reporting rate for this side effect is 7.4 per million for Pfizer and 20 per million for Moderna.

The highlights section of the PHO report conclude with a note that “COVID-19 vaccines continue to be recommended and are highly effective at preventing symptomatic infection and severe outcomes from COVID-19 disease, which is also associated with a risk of myocarditis.”

Source : Toronto Sun

Study: Vaccines’ Power Against COVID Hospitalization Fades in Elderly

The ability of COVID-19 vaccines to protect adults older than 75 against hospitalization appears to wane over time, but still remained 80% effective as of the end of July, new federal data shows.

The same data indicates that vaccines continued to offer the same or nearly the same level of protection against hospitalization for people up to the age of 75, and the shots remained 94% effective among adults ages 18-49, CBS News reported.

Hospitalization rates among fully vaccinated people were higher among older residents of nursing homes and among those with underlying conditions such as weakened immune systems, according to data compiled by the U.S. Centers for Disease Control and Prevention.

Getting vaccinated remains crucial: Previewing the data’s release earlier this month, CDC Director Dr. Rochelle Walensky noted that “COVID-19-associated hospitalization rates were 17 times higher in unvaccinated,”CBS News reported.

The fresh data was presented Monday as the CDC’s independent panel of vaccine experts met to discuss federal plans for a potential booster dose of COVID-19 vaccines next month.

While the findings suggest a slight decline in the vaccines’ ability to protect older and vulnerable people against severe disease, the CDC says reaching conclusions about how long protection lasts in these groups is challenging, CBS News reported.

“It actually may be very difficult for us to disentangle time, since vaccination and the impact of the Delta variant, especially in some populations that we know were vaccinated earlier in the time course. So, if we see waning in the last couple of months, it could be really difficult,” Dr. Sara Oliver, a leading CDC vaccine official, told the vaccine panel.

Another CDC analysis released on the weekend stated that even though 16.1% of hospitalized COVID-19 patients in June had been fully vaccinated, the vaccines appear to remain “highly effective in preventing hospitalization,” CBS News reported.

On Monday, the CDC said it will schedule another meeting of the panel in mid-September to discuss more data on booster shots, a meeting that will likely be held before the Biden administration’s planned roll-out of booster shots the week of Sept. 20.

Previously, top U.S. health officials said they were planning for the possibility that third doses of the Pfizer and Moderna vaccines would be needed eight months after people received their first two shots, but recent data from the vaccine makers and other countries suggest booster shots might be required sooner than six months from vaccination, CBS News reported.

Source: HealthDay