---
type: "Bill"
title: "Revise laws on medical exemption from vaccines"
description: "Revise laws on medical exemption from vaccines"
jurisdiction: "us/states/mt"
legislature: "Montana Legislature"
session: "2021"
identifier: "HB 334"
citation: "Montana HB 334 (2021)"
classification: ["bill"]
subjects: ["Health (see also: Health Care Services; Safety)", "Health Care Services (see also: Health)", "Schools and Education"]
status: "enacted"
primary_sponsors: ["Jennifer Carlson"]
version_count: 6
action_count: 57
vote_count: 9
first_action: "2020-10-13"
last_action: "2021-04-29"
source: "openstates"
source_identifier: "ocd-bill/21fdf2e1-6c88-417a-9924-6c60365a2a07"
source_url: "http://laws.leg.mt.gov/legprd/LAW0210W$BSIV.ActionQuery?P_BILL_NO1=334&P_BLTP_BILL_TYP_CD=HB&Z_ACTION=Find&P_SESS=20211"
source_hash: "65de369659301ae7c399fb3a139f3be82fc7d3bf4cb2342ff0d697e5ece33744"
vintage: "2026-07-01"
source_snapshot: "https://data.openstates.org/daily/2026-07-01/public.pgdump"
retrieved_at: "2026-07-06"
confidence: "reported"
tags: ["legislation", "bill", "us-mt"]
---

# Montana HB 334 (2021) — Revise laws on medical exemption from vaccines

## Version chain

The bill's text revisions, in order — the diff chain from filing to enrollment.

1. **HB0334_1.pdf** (committee substitute) — [source](https://leg.mt.gov/bills/2021/HB0399//HB0334_1.pdf)
2. **HB0334_2.pdf** (committee substitute) — [source](https://leg.mt.gov/bills/2021/HB0399//HB0334_2.pdf)
3. **HB0334_3.pdf** (committee substitute) — [source](https://leg.mt.gov/bills/2021/HB0399//HB0334_3.pdf)
4. **HB0334_4.pdf** (committee substitute) — [source](https://leg.mt.gov/bills/2021/HB0399//HB0334_4.pdf)
5. **HB0334_X.pdf** (committee substitute) — [source](https://leg.mt.gov/bills/2021/HB0399//HB0334_X.pdf)
6. **Enrolled** (enrolled) — [source](https://leg.mt.gov/bills/2021/billpdf/HB0334.pdf)

## Votes

- Do Pass — **29–19** (pass) · upper
- BE CONCURRED IN AS AMENDED — **6–3** (pass) · upper
- Do Pass — **65–34** (pass) · lower
- Do Concur — **65–33** (pass) · lower
- AMD-002 Carlson D/PASS — **98–1** (pass) · lower
- Do Concur — **29–21** (pass) · upper
- Do Pass As Amended — **65–35** (pass) · lower
- Do Concur — **67–32** (pass) · lower
- DO PASS AS AMENDED — **12–7** (pass) · lower

## Sponsors

- Jennifer Carlson — primary (person)

## Timeline

The legislative action history — every referral, reading, and vote.

- **2020-10-13** Draft Request Received
- **2020-10-21** Draft to Requester for Review
- **2020-11-04** Draft On Hold
- **2021-01-26** Draft to Requester for Review
- **2021-01-29** Draft to Requester for Review
- **2021-01-29** Draft in Legal Review
- **2021-01-30** Draft in Edit
- **2021-02-02** Draft to Drafter - Edit Review
- **2021-02-02** Draft in Input/Proofing
- **2021-02-02** Draft in Final Drafter Review
- **2021-02-02** Bill Draft Text Available Electronically
- **2021-02-02** Executive Director Review
- **2021-02-03** Draft in Assembly
- **2021-02-03** Draft Ready for Delivery
- **2021-02-03** Executive Director Final Review
- **2021-02-03** Draft Ready for Delivery
- **2021-02-05** Draft Delivered to Requester
- **2021-02-08** Introduced `introduction`
- **2021-02-08** Introduced Bill Text Available Electronically
- **2021-02-08** Referred to Committee - (H) Human Services `referral-committee`
- **2021-02-08** First Reading `reading-1`
- **2021-02-09** Sponsor List Modified
- **2021-02-16** Hearing - (H) Human Services
- **2021-02-21** Amendments Available
- **2021-02-22** Committee Executive Action--Bill Passed as Amended - (H) Human Services `committee-passage`
- **2021-02-23** Committee Report--Bill Passed as Amended - (H) Human Services `committee-passage`
- **2021-02-23** Printed - New Version Available
- **2021-02-25** Scheduled for 2nd Reading
- **2021-02-25** 2nd Reading Motion to Amend Carried
- **2021-02-25** 2nd Reading Passed as Amended `reading-2`
- **2021-02-25** Printed - New Version Available
- **2021-02-27** Scheduled for 3rd Reading
- **2021-02-27** 3rd Reading Passed `passage, reading-3`
- **2021-02-27** Transmitted to Senate
- **2021-03-01** First Reading `reading-1`
- **2021-03-17** Referred to Committee - (S) Public Health, Welfare and Safety `referral-committee`
- **2021-03-31** Hearing - (S) Public Health, Welfare and Safety
- **2021-03-31** Committee Executive Action--Bill Concurred as Amended - (S) Public Health, Welfare and Safety
- **2021-04-01** Committee Report--Bill Concurred as Amended - (S) Public Health, Welfare and Safety
- **2021-04-01** Printed - New Version Available
- **2021-04-07** Scheduled for 2nd Reading
- **2021-04-07** 2nd Reading Concurred `reading-2`
- **2021-04-08** Scheduled for 3rd Reading
- **2021-04-08** 3rd Reading Concurred `passage, reading-3`
- **2021-04-08** Returned to House with Amendments
- **2021-04-12** Scheduled for 2nd Reading
- **2021-04-12** 2nd Reading Senate Amendments Concurred `amendment-amendment, amendment-passage, reading-2`
- **2021-04-13** Scheduled for 3rd Reading
- **2021-04-13** 3rd Reading Passed as Amended by Senate `passage, reading-3`
- **2021-04-13** Sent to Enrolling
- **2021-04-15** Returned from Enrolling
- **2021-04-15** Printed - Enrolled Version Available
- **2021-04-20** Signed by Speaker
- **2021-04-21** Signed by President
- **2021-04-22** Transmitted to Governor `executive-receipt`
- **2021-04-28** Signed by Governor `executive-signature`
- **2021-04-29** Chapter Number Assigned `became-law`

## Source

OpenStates / OpenCivicData bulk snapshot [2026-07-01](https://data.openstates.org/daily/2026-07-01/public.pgdump); origin `ocd-bill/21fdf2e1-6c88-417a-9924-6c60365a2a07`. Confidence: reported (aggregated from official Montana legislature records).