IBOV 169,029.02 ▼ 1.16% IPC MEX 69,182.39 ▼ 0.76% MERVAL 2,848,945 — — USD/BRL5.39▲ 0.84% USD/MXN18.85▲ 1.14% USD/CLP990.37▲ 0.26% USD/COP3,165▲ 0.50% USD/PEN3.46▲ 0.28% USD/ARS1,538▼ 0.24% USD/UYU40.10▲ 3.30% USD/PYG5,838▲ 3.76% USD/BOB12.05▲ 4.53% USD/DOP60.36▲ 0.43% USD/CRC451.45▲ 2.55% USD/GTQ7.64▲ 3.31% USD/HNL26.87▲ 0.27% USD/NIO36.62▼ 0.02% USD/VES886.67▼ 0.13% USD/PAB1.00— 0.00% USD/BZD2.00— 0.00% USD/JMD157.79▲ 2.42% USD/TTD6.70▲ 2.01% EUR/BRL6.02▲ 1.21% BRENT 109.58 ▼ 5.38% WTI 100.12 ▼ 1.61% IRON ORE 161.91 — — COPPER 6.65 ▲ 2.24% GOLD 4,073 ▲ 0.85% SILVER 54.49 ▲ 0.70% SOY 1,250 ▲ 0.70% CORN 450.25 ▼ 1.04% WHEAT 614.75 ▼ 0.20% COFFEE 294.35 ▼ 2.19% SUGAR 19.26 ▲ 0.84% ORANGE JUICE 143.20 ▲ 5.45% COTTON 77.90 ▼ 1.47% COCOA 5,581 ▲ 1.66% BEEF 230.73 ▲ 0.33% CATTLE 346.40 ▼ 1.00% LITHIUM 62.43 ▲ 1.89% PETR4 53.31 ▼ 1.06% VALE3 62.88 ▼ 2.33% ITUB4 41.42 ▼ 0.67% BBDC4 15.69 ▼ 1.63% ABEV3 15.40 ▲ 0.20% BBAS3 17.59 ▲ 0.69% B3SA3 15.27 ▲ 1.33% WEGE3 45.78 ▲ 2.81% PRIO3 69.21 ▼ 2.71% SUZB3 47.14 ▼ 0.55% RENT3 31.14 ▼ 1.67% AZZA3 16.72 ▲ 1.15% CSAN3 2.69 ▼ 2.89% RAIZ4 0.34 — 0.00% PCAR3 2.22 ▼ 3.48% GMAT3 3.74 ▲ 2.19% PSSA3 47.75 ▼ 0.89% CVCB3 0.98 — 0.00% POSI3 3.56 ▼ 0.84% SLCE3 16.97 ▼ 2.75% NATU3 5.68 ▼ 3.89% BRKM5 3.80 ▲ 19.50% RANI3 7.34 ▼ 0.54% CSNA3 4.76 ▼ 4.99% IBOV 169,029.02 ▼ 1.16% IPC MEX 69,182.39 ▼ 0.76% MERVAL 2,848,945 — — USD/BRL 5.34 ▼ 1.32% USD/MXN 18.69 ▲ 0.62% USD/CLP 983.47 ▼ 0.57% USD/COP 3,149 ▲ 3.06% USD/PEN 3.45 ▲ 0.17% USD/ARS 1,537 ▼ 0.28% USD/UYU 40.21 ▲ 3.57% USD/PYG 5,803 ▲ 3.78% USD/BOB 11.97 ▲ 4.93% USD/DOP 60.54 ▲ 1.83% USD/CRC 451.24 ▲ 2.13% USD/GTQ 7.64 ▲ 3.23% USD/HNL 26.87 ▲ 3.37% USD/NIO 36.62 ▲ 2.81% USD/VES 885.08 ▼ 0.13% USD/PAB 1.00 — 0.00% USD/BZD 2.00 — 0.00% USD/JMD 157.69 ▲ 2.63% USD/TTD 6.71 ▲ 2.07% EUR/BRL 5.95 ▲ 7.53% BRENT 109.58 ▼ 5.38% WTI 100.12 ▼ 1.61% IRON ORE 161.91 — — COPPER 6.65 ▲ 2.24% GOLD 4,073 ▲ 0.85% SILVER 54.49 ▲ 0.70% SOY 1,250 ▲ 0.70% CORN 450.25 ▼ 1.04% WHEAT 614.75 ▼ 0.20% COFFEE 294.35 ▼ 2.19% SUGAR 19.26 ▲ 0.84% ORANGE JUICE 143.20 ▲ 5.45% COTTON 77.90 ▼ 1.47% COCOA 5,581 ▲ 1.66% BEEF 230.73 ▲ 0.33% CATTLE 346.40 ▼ 1.00% LITHIUM 62.43 ▲ 1.89% PETR4 53.31 ▼ 1.06% VALE3 62.88 ▼ 2.33% ITUB4 41.42 ▼ 0.67% BBDC4 15.69 ▼ 1.63% ABEV3 15.40 ▲ 0.20% BBAS3 17.59 ▲ 0.69% B3SA3 15.27 ▲ 1.33% WEGE3 45.78 ▲ 2.81% PRIO3 69.21 ▼ 2.71% SUZB3 47.14 ▼ 0.55% RENT3 31.14 ▼ 1.67% AZZA3 16.72 ▲ 1.15% CSAN3 2.69 ▼ 2.89% RAIZ4 0.34 — 0.00% PCAR3 2.22 ▼ 3.48% GMAT3 3.74 ▲ 2.19% PSSA3 47.75 ▼ 0.89% CVCB3 0.98 — 0.00% POSI3 3.56 ▼ 0.84% SLCE3 16.97 ▼ 2.75% NATU3 5.68 ▼ 3.89% BRKM5 3.80 ▲ 19.50% RANI3 7.34 ▼ 0.54% CSNA3 4.76 ▼ 4.99%
since 2009
Thursday, October 29, 2026

Up to 95% of serious adverse drug events go unreported

By · October 22, 2021 · 4 min read

RIO DE JANEIRO, BRAZIL – Drug reporting systems designed to capture adverse events in the population are notoriously unreliable. With the introduction of Covid vaccines, adverse effects have also become a hot topic, mainly because vaccine injury reporting systems are unreliable.

How common is it for mild, severe, or life-threatening adverse reactions to drugs or vaccines to go unreported? This is an important question because, without reporting, researchers cannot disseminate critical cost-benefit analyses of drugs to the general population.

A 2006 study published in the journal Drug Safety included more than 37 studies from 12 different countries that used various surveillance methods.

Up to 95% of serious adverse drug events go unreported
Up to 95% of serious adverse drug events go unreported.
RT
Ask Rio Times
17 years of Latin America reporting, on demand.
Open the full Ask Rio Times →

They found evidence of widespread and substantial underreporting of adverse drug reactions (ADRs). These included severe ADRs.

The median underreporting rate in the 37 studies was 94% (82-98%). There was no significant difference between the median underreporting rates calculated for general practice and hospital studies.

The LatAm Brief

One email, every weekday morning. What moved in Latin American markets, politics and expat life.

Yesterday’s subject line: “Bolsonaro's son lands in Miami despite passport order”

Free. We send a confirmation link first — nothing arrives until you click it. Unsubscribe with one click in any edition. If you stop opening us for 30 days we stop sending by ourselves, as we assume the interest is no longer there. See our privacy policy. We never share your email.

Five of the ten general practice studies provided evidence of a higher mean underreporting rate for all ADRs compared with the most severe or severe ADRs (95% and 80%, respectively). In comparison, in five of the eight hospital-based studies, the mean underreporting rate for more severe or severe AMRs remained high (95%).

In 19 studies examining specific drug combinations with severe/serious adverse events, the median under-reporting rate was lower but still high (85%).

This is concerning given that prescription drugs are the third leading cause of death in the U.S. and Europe, after heart disease and cancer.

A 2018 study published in the International Journal of Medical Science Research attempts to answer why this is happening. Again, this is a well-known problem among those who study it, and the data are pretty similar across publications.

The 2018 study found that physicians “know very little about AMR reporting.” They found that 32.8 percent of respondents did not know if the reaction was caused by the drug or that 46.3 percent felt it was unnecessary to report recognized reactions.

Overall, “deficient physician awareness of pharmacovigilance was found,” The researchers emphasized the need to improve physician awareness. Adequate and accessible reporting systems need to be in place to enhance reporting.

WHAT ABOUT VACCINES?

The Vaccine Adverse Event Reporting System (VAERS) of the CDC and FDA is the nationwide early warning system that monitors the safety of vaccines once they are licensed or cleared for use by the FDA.

It is a self-reporting system that does not prove causality but is designed to detect signs of adverse events (e.g., thrombotic events in the COVID-19 vaccine and myocarditis). “VAERS scientists are looking for an unusually high number of adverse event reports following a particular vaccine or a new pattern of adverse events.”

Physicians must report adverse reactions to vaccines to VAERS, but because it is a self-reporting system, it has been criticized because anyone can report a vaccine reaction. The CDC has clarified that a reported event related to vaccine administration does not mean that the vaccine caused the adverse reaction.

Still, it is concerning that VAERS received 2,149 reports of deaths between 1997 and 2013, and no “pattern of concern” was found. But as Senator Ron Johnson wrote on August 22, 2021, there were: “12,791 Covid-19 vaccine-related deaths reported in VAERS over eight months, 16,044 permanent disabilities, 51,242 hospitalizations, and a total of 571,831 adverse events related to Covid-19 vaccines.”

Approximately 17,000 deaths, 25,000 permanent disabilities, and 80,000 hospitalizations related to Covid vaccines have been reported to VAERS in the United States alone.

In a 2011 report titled “Electronic Public Health Support – Vaccine Adverse Event Reporting System (ESP: VAERS),” Harvard medical professors Ross Lazarus, Michael Klompas, and Steve Bernstein report that vaccines are underreported:

Consider that on July 16, 1999, the CDC recommended that health care providers discontinue the use of the approved RotaShield vaccine, a rotavirus vaccine, after only 15 cases of intestinal obstruction were reported to VAERS.

Of course, there is a way for researchers to use VAERS properly. Still, however you look at it, the numbers in VAERS on COVID vaccines are pretty disturbing and staggering. Even though the number of adverse events with vaccines may be minimal, one must consider the number of reports that are probably not related to the vaccine.

The question is how likely it is that a physician will report a suspected adverse effect from the vaccine. If a patient comes in three days after vaccination with some complaint, will most physicians even entertain the idea that the event might be vaccine-related?

Physicians may be biased to believe that severe vaccine injury is infrequent. The CDC claims it is 1 in a million, but how can they claim such a number when there are no proper adverse event reporting systems? Why do they not provide sources or data to support their claim?

It is also important to point out that proper reporting systems are not something that pharmaceutical companies would openly advocate. They have multiple criminal convictions and have falsified information about their drugs, including efficacy. That would be bad for business, and as far as business is concerned, Pfizer has paid one of the highest criminal fines in history.

This article was produced by The Rio Times’ automated newsroom system. How we use AI · Report an error · Editorial responsibility: Matthias Camenzind, Editor-in-Chief

Read More from The Rio Times

Brazil runoff date: Sunday, October 25, poll closing times and when results start · Brazil runoff polls: Flávio 51%, Lula 49% · Kalshi and Polymarket odds

Rotate for Best Experience

This report is optimized for landscape viewing. Rotate your phone for the full experience.