<PAGE>
MFS(R) MUNICIPAL SERIES TRUST
MFS ALABAMA MUNICIPAL BOND FUND
MFS(R) ARKANSAS MUNICIPAL BOND FUND
MFS(R) CALIFORNIA MUNICIPAL BOND FUND
MFS(R) FLORIDA MUNICIPAL BOND FUND
MFS(R) GEORGIA MUNICPAL BOND FUND
MFS(R) MARYLAND MUNICIPAL BOND FUND
MFS(R) MASSACHUSETTS MUNICIPAL BOND FUND
MFS(R) MISSISSIPPI MUNICIPAL BOND FUND
MFS(R) NEW YORK MUNICIPAL BOND FUND
MFS(R) NORTH CAROLINA MUNICIPAL BOND FUND
MFS(R) PENNSYLVANIA MUNICIPAL BOND FUND
MFS(R) SOUTH CAROLINA MUNICIPAL BOND FUND
MFS(R) TENNESSEE MUNICIPAL BOND FUND
MFS(R) VIRGINIA MUNICIPAL BOND FUND
MFS(R) WEST VIRGINIA MUNICIPAL BOND FUND
Supplement to the Current Prospectus
The description of portfolio managers under "Management of the Trust -
Investment Adviser" section is hereby restated as follows:
Effective January 1, 1999, the portfolio managers for each Fund are John P. Kihn
and Michael L. Dawson, Vice Presidents of the Adviser. Mr. Kihn has been a
portfolio manager of the Florida Fund and the Tennessee Fund since 1997, and has
been a portfolio manager of each of the other Funds since 1998. Mr. Dawson
became a portfolio manager of each Fund as of January 1, 1999. Prior to joining
MFS in 1997, Mr. Kihn was a Quantitative Analyst and Vice President of Putnam
Investments from 1996 to 1997; from 1992 to 1996, he attended the London School
of Economics where he was awarded a doctorate in Finance; and from 1994 to 1995,
he was an Associate Portfolio Manager with Colonial Management Associates, Inc.
Mr. Dawson has been employed as a portfolio manager with the Adviser since
September, 1998. Prior to September, 1998, Mr. Dawson was employed as a sales
representative in the Institutional Sales Group at Fidelity Capital Markets from
March, 1997 to May, 1998. From January, 1993 to March, 1997, Mr. Dawson was
employed by Goldman Sachs & Co. in the Institutional Sales - Fixed Income
Division.
Effective January 1, 1999, the Massachusetts state tax rate on dividends and
income is reduced to 5.95%. The Tax Equivalent Yield Table for Massachusetts
contained in Appendix B to the Prospectus which appears on page B-4 is revised
in its entirety as follows:
MASSACHUSETTS - 1999 TAX YEAR
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<TABLE>
<S> <C> <C> <C> <C> <C> <C> <C>
INCOME MASSACHUSETTS TAX-EXEMPT YIELD Average Combined
TAXABLE INCOME* TAX Federal State Fed. & St.
SINGLE JOINT BRACKET** 3.0% 4.0% 5.0% 6.0% 7.0% 8.0% Rate Rate Rate ***
1999 1999
$0-25,750 $0-43,050 20.06% 3.75% 5.00% 6.25% 7.51% 8.76% 10.01% 0.15 0.059500 0.2006
$25,750-62,450 $43,050-104,050 32.28% 4.43% 5.91% 7.38% 8.86% 10.34% 11.81% 0.28 0.059500 0.3228
$62,450-130,250 $104,050-158,550 35.11% 4.62% 6.16% 7.71% 9.25% 10.79% 12.33% 0.31 0.059500 0.3511
$130,250-283,150 $158,550-283,150 39.81% 4.98% 6.65% 8.31% 9.97% 11.63% 13.29% 0.36 0.059500 0.3981
$283,150 & OVER $283,150 & OVER 43.19% 5.28% 7.04% 8.80% 10.56% 12.32% 14.08% 0.396 0.059500 0.4319
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</TABLE>
* Net amount subject to Federal and Massachusetts personal income tax after
deductions and exemptions.
** Effective combined federal and state tax bracket. State rate based on the
average state rate for the federal tax bracket.
*** Combined Federal and Massachusetts rate assumes itemization of state tax
deduction.
The date of this Supplement is January 1, 1999.
