Pharmacovigilance Record

mRNA Vaccine Batch Issues During the Rapid Rollout

The main documented cases of specific mRNA COVID-19 vaccine batches — primarily Moderna — with issues during the rapid rollout involved contamination or clusters of adverse reactions, leading to temporary pauses or recalls. These were relatively rare and addressed through standard pharmacovigilance processes.

Claims of widespread "hot lots" with systematically higher risks — especially for Pfizer — come mostly from analyses of spontaneous reporting systems like VAERS or Danish data, which regulators and follow-up studies have generally not confirmed as indicating true safety differences, due to reporting biases, batch size variations, and other confounding factors. PubMed / NCBI

Confirmed Batch-Specific Issues (Recalls & Pauses)

The following events are documented through official regulatory actions, press releases, and court-accessible public records.

Moderna Lot 041L20A

United States — California — Early 2021

Paused / Investigated

California health officials recommended pausing use of this lot after a cluster of apparent allergic reactions — fewer than 10 people seeking care — at a single San Diego clinic. The lot had distributed approximately 330,000+ doses across the state (part of ~1.27 million produced). No similar clusters were widely reported elsewhere, and federal reviews by the CDC and FDA did not recommend a full stop. The lot was investigated but not subject to a full recall in all jurisdictions.

Source: Los Angeles Times

Moderna Batches 3004667, 3004734, 3004956

Japan — September 2021

Recalled / Suspended

Three batches totalling approximately 1.63 million doses were recalled and suspended after stainless steel particles were found in some vials, traced to a Spanish manufacturing site operated by Rovi. Use was paused after reports of foreign material; over 500,000 doses had already been administered. No major safety issues tied to the contamination were reported. These batches were not distributed in the United Kingdom.

Source: Reuters

Moderna Lot 000190A

Europe — 2022

Recalled

One lot was recalled due to a foreign body found in a vial, again linked to a contract manufacturer. This was an isolated incident with no broader safety signal identified.

Source: Fierce Pharma

Pfizer-BioNTech (Comirnaty / BNT162b2)

Global — 2021–2022

No Major Recalls

Pfizer had no major public recalls for contamination comparable to the Moderna events above. A 2023 Danish observational analysis reported higher adverse-event rates for certain smaller or earlier batches versus larger later ones, sparking discussion of possible manufacturing variability during scale-up. However, larger cohort studies — including follow-ups in Denmark — and agencies such as Germany's Paul-Ehrlich-Institut found no clinically meaningful batch-specific safety differences after accounting for doses administered. Adverse events scaled with usage volume rather than batch identity.

Source: Wiley Online Library

Context on Fast Rollout & Batch Variability

Rapid production scaling led to quality control scrutiny, with every batch still undergoing release testing.

VAERS & Spontaneous Reporting

Spontaneous reports (VAERS, Yellow Card, etc.) show some batches with more associated events, but this often correlates with how widely distributed a batch was — or how many doses were given from it — rather than inherent defects.

FDA.gov

Regulatory Findings

Official analyses emphasise that serious side effects remain rare overall. Known signals such as myocarditis/pericarditis — higher with Moderna in young males — are not strongly tied to specific batches.

FDA.gov

Danish Cohort Studies

A 2023 Danish observational analysis reported higher adverse-event rates for certain batches. Larger follow-up cohort studies and Germany's Paul-Ehrlich-Institut found no clinically meaningful batch-specific differences after adjusting for doses administered.

PubMed / NCBI

Manufacturing Scale-Up

Every batch underwent standard release testing regardless of production speed. Contamination events (stainless steel particles, foreign bodies) were isolated to specific contract manufacturers and addressed through standard recall procedures.

Reuters

Your Vaccine Record Card: Where Batch Information Was Recorded

Every COVID-19 vaccination came with a CDC-issued Vaccine Record Card. This card is where your specific batch (lot) number was recorded at the time of administration — the same lot numbers referenced in the recalls and adverse-event clusters documented on this page.

CDC COVID-19 Vaccination Record Card

"This is where your specific batch information was recorded."

The Lot Number field on your card corresponds directly to the manufacturing batch your dose came from. The lot numbers recalled in Japan (e.g. 3004667, 3004734, 3004956) and the California pause lot (041L20A) are the same format as what appears on your card.

What to look for on your card

Product Name / Manufacturer: Moderna, Pfizer-BioNTech (Comirnaty), or Janssen
Lot Number: The specific batch — cross-reference against documented recalls above
Date: Helps narrow which production run your dose came from
Healthcare Professional or Clinic Site: May assist in obtaining your full vaccination record if the card is lost

Lost your card? Your lot number may still be retrievable through your state's immunization registry, your provider's records, or the CDC V-safe program if you enrolled at the time of vaccination.

This page summarises publicly documented regulatory actions and peer-reviewed research. It does not constitute legal or medical advice. If you believe you experienced a vaccine injury, see our free resources or case directory.

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